diff --git a/src/plugins/data/public/query/query_service.ts b/src/plugins/data/public/query/query_service.ts
index 1da535f3f9e..7264b2305ca 100644
--- a/src/plugins/data/public/query/query_service.ts
+++ b/src/plugins/data/public/query/query_service.ts
@@ -88,7 +88,7 @@ export class QueryService {
     uiSettings,
     indexPatterns,
   }: QueryServiceStartDependencies): IQueryStart {
-    this.queryStringManager.initDataset();
+    this.queryStringManager.getDatasetService().init();
     return {
       addToQueryLog: createAddToQueryLog({
         storage,
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.mock.ts b/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.mock.ts
deleted file mode 100644
index bb522f4ad8e..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.mock.ts
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-// import { DatasetContract } from '.';
-// import { Dataset, DataStructure, CachedDataStructure } from '../../../../common';
-// import { DatasetTypeConfig } from './types';
-
-// const createSetupContractMock = () => {
-//   const datasetManagerMock: jest.Mocked<DatasetContract> = {
-//     init: jest.fn(),
-//     getDataset: jest.fn(),
-//     setDataset: jest.fn(),
-//     getUpdates$: jest.fn(),
-//     getDefaultDataset: jest.fn(),
-//     fetchDefaultDataset: jest.fn(),
-//     init: jest.fn(),
-//     registerDatasetHandler: jest.fn(),
-//     fetchOptions: jest.fn(),
-//     getCachedDataStructure: jest.fn(),
-//     clearDataStructureCache: jest.fn(),
-//   };
-//   return datasetManagerMock;
-// };
-
-// export const datasetManagerMock = {
-//   createSetupContract: createSetupContractMock,
-//   createStartContract: createSetupContractMock,
-// };
-
-// // Additional mock for DatasetHandlerConfig
-// export const createDatasetHandlerConfigMock = (): jest.Mocked<DatasetTypeConfig> => ({
-//   toDataset: jest.fn(),
-//   toDataStructure: jest.fn(),
-//   fetchOptions: jest.fn(),
-//   isLeaf: jest.fn(),
-// });
-
-// // Mock for Dataset
-// export const createDatasetMock = (): jest.Mocked<Dataset> => ({
-//   id: 'mock-dataset-id',
-//   title: 'Mock Dataset',
-//   type: 'mock-type',
-//   dataSource: {
-//     id: 'mock-datasource-id',
-//     title: 'Mock DataSource',
-//     type: 'mock-datasource-type',
-//   },
-// });
-
-// // Mock for DataStructure
-// export const createDataStructureMock = (): jest.Mocked<DataStructure> => ({
-//   id: 'mock-datastructure-id',
-//   title: 'Mock DataStructure',
-//   type: 'mock-type',
-//   parent: undefined,
-//   children: [],
-// });
-
-// // Mock for CachedDataStructure
-// export const createCachedDataStructureMock = (): jest.Mocked<CachedDataStructure> => ({
-//   id: 'mock-cached-datastructure-id',
-//   title: 'Mock Cached DataStructure',
-//   type: 'mock-type',
-//   parent: 'mock-parent-id',
-//   children: ['mock-child-id-1', 'mock-child-id-2'],
-// });
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.test.ts b/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.test.ts
deleted file mode 100644
index 287f733fcc5..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.test.ts
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-// import { DatasetManager } from './dataset_manager';
-// import { coreMock } from '../../../../../../core/public/mocks';
-// import { Dataset } from '../../../../common';
-
-// describe('DatasetManager', () => {
-//   let service: DatasetManager;
-
-//   beforeEach(() => {
-//     const uiSettingsMock = coreMock.createSetup().uiSettings;
-//     uiSettingsMock.get.mockReturnValue(true);
-//     service = new DatasetManager(uiSettingsMock);
-//   });
-
-//   test('getUpdates$ is a cold emits only after dataset changes', () => {
-//     const obs$ = service.getUpdates$();
-//     const emittedValues: Dataset[] = [];
-//     obs$.subscribe((v) => {
-//       emittedValues.push(v!);
-//     });
-//     expect(emittedValues).toHaveLength(0);
-//     expect(emittedValues[0]).toEqual(undefined);
-
-//     const newDataset: Dataset = {
-//       id: 'test_dataset',
-//       title: 'Test Dataset',
-//       type: 'INDEX_PATTERN',
-//     };
-//     service.setDataset(newDataset);
-//     expect(emittedValues).toHaveLength(1);
-//     expect(emittedValues[0]).toEqual(newDataset);
-
-//     service.setDataset({ ...newDataset });
-//     expect(emittedValues).toHaveLength(2);
-//   });
-// });
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.ts b/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.ts
deleted file mode 100644
index e8106a6fb64..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/dataset_manager.ts
+++ /dev/null
@@ -1,238 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-import { BehaviorSubject } from 'rxjs';
-import { CoreStart, SavedObjectsClientContract } from 'opensearch-dashboards/public';
-import { skip } from 'rxjs/operators';
-import {
-  Dataset,
-  DEFAULT_DATA,
-  DataStructure,
-  CachedDataStructure,
-  DataStructureCache,
-  createDataStructureCache,
-  IndexPatternSpec,
-} from '../../../../common';
-import { IndexPatternsContract } from '../../../index_patterns';
-import { indexPatternHandlerConfig, indexHandlerConfig } from './lib';
-import { DatasetTypeConfig } from './types';
-
-/**
- * Manages datasets and their associated handlers.
- */
-export class DatasetManager {
-  private dataset$: BehaviorSubject<Dataset | undefined>;
-  private indexPatterns?: IndexPatternsContract;
-  private defaultDataset?: Dataset;
-  private dataStructureCache: DataStructureCache;
-  private datasetHandlers: Map<string, DatasetTypeConfig>;
-  private dataStructuresMap: Map<string, DataStructure>;
-
-  /**
-   * Creates an instance of DatasetManager.
-   * @param uiSettings - The CoreStart's uiSettings.
-   * @param savedObjects - The SavedObjectsClientContract.
-   */
-  constructor(private readonly uiSettings: CoreStart['uiSettings']) {
-    this.dataset$ = new BehaviorSubject<Dataset | undefined>(undefined);
-    this.dataStructureCache = createDataStructureCache();
-    this.datasetHandlers = new Map();
-    this.dataStructuresMap = new Map();
-    this.registerDefaultHandlers();
-  }
-
-  /**
-   * Registers default handlers for index patterns and indices.
-   */
-  private registerDefaultHandlers() {
-    this.registerDatasetHandler(indexPatternHandlerConfig);
-    this.registerDatasetHandler(indexHandlerConfig);
-  }
-
-  /**
-   * Registers a dataset handler.
-   * @param handler - The dataset handler configuration.
-   */
-  public registerDatasetHandler(handler: DatasetTypeConfig) {
-    this.datasetHandlers.set(handler.id, handler);
-  }
-
-  /**
-   * Gets all registered dataset handlers.
-   * @returns An array of dataset handler configurations.
-   */
-  public getDatasetHandlers(): DatasetTypeConfig[] {
-    return Array.from(this.datasetHandlers.values());
-  }
-
-  /**
-   * Gets a dataset handler by its ID.
-   * @param id - The ID of the dataset handler.
-   * @returns The dataset handler configuration, or undefined if not found.
-   */
-  public getDatasetHandlerById(id: string): DatasetTypeConfig | undefined {
-    return this.datasetHandlers.get(id);
-  }
-
-  /**
-   * Fetches options for a given data structure.
-   * @param dataStructure - The data structure to fetch options for.
-   * @returns A promise that resolves to a DatasetHandlerFetchResponse.
-   */
-  public fetchOptions(
-    savedObjects: SavedObjectsClientContract,
-    path: DataStructure[]
-  ): Promise<DataStructure> {
-    const dataStructure = path[path.length - 1];
-    const handler = this.getHandlerForDataStructure(dataStructure);
-    return handler.fetch(savedObjects, path);
-  }
-
-  /**
-   * Checks if a given data structure is a leaf node.
-   * @param dataStructure - The data structure to check.
-   * @returns True if the data structure is a leaf node, false otherwise.
-   */
-  public isLeafDataStructure(dataStructure: DataStructure): boolean {
-    const handler = this.getHandlerForDataStructure(dataStructure);
-    return handler.id === dataStructure.type;
-  }
-
-  /**
-   * Converts a data structure to a dataset.
-   * @param dataStructure - The data structure to convert.
-   * @returns A promise that resolves to a BaseDataset.
-   */
-  public toDataset(path: DataStructure[]): Dataset {
-    const dataStructure = path[path.length - 1];
-    const handler = this.getHandlerForDataStructure(dataStructure);
-    return handler.toDataset(path);
-  }
-
-  /**
-   * Gets the appropriate handler for a given data structure.
-   * @param dataStructure - The data structure to get the handler for.
-   * @returns The dataset handler configuration.
-   * @throws Error if no handler is found.
-   */
-  private getHandlerForDataStructure(dataStructure: DataStructure): DatasetTypeConfig {
-    const handler =
-      this.datasetHandlers.get(dataStructure.type) ||
-      this.datasetHandlers.get(DEFAULT_DATA.SET_TYPES.INDEX_PATTERN);
-    if (!handler) {
-      throw new Error(`No handler found for type: ${dataStructure.type}`);
-    }
-    return handler;
-  }
-
-  /**
-   * Sets the current dataset.
-   * @param dataset - The dataset to set.
-   */
-  public async setDataset(dataset: Dataset | undefined) {
-    if (dataset) {
-      const spec = {
-        ...dataset,
-        dataSourceRef: dataset.dataSource
-          ? {
-              id: dataset.dataSource.id!,
-              name: dataset.dataSource.title,
-              type: dataset.dataSource.type,
-            }
-          : undefined,
-      } as IndexPatternSpec;
-      const temporaryIndexPattern = await this.indexPatterns!.create(spec, true);
-      this.indexPatterns?.saveToCache(dataset.id, temporaryIndexPattern);
-    }
-    this.dataset$.next(dataset);
-  }
-
-  /**
-   * Gets the current dataset.
-   * @returns The current dataset, or undefined if not set.
-   */
-  public getDataset(): Dataset | undefined {
-    return this.dataset$.getValue();
-  }
-
-  /**
-   * Gets an observable of dataset updates.
-   * @returns An observable of dataset updates.
-   */
-  public getUpdates$() {
-    return this.dataset$.asObservable().pipe(skip(1));
-  }
-
-  /**
-   * Gets a cached data structure by ID.
-   * @param id - The ID of the data structure to retrieve.
-   * @returns The cached data structure, if found.
-   */
-  public getCachedDataStructure(id: string): CachedDataStructure | undefined {
-    return this.dataStructureCache.get(id);
-  }
-
-  /**
-   * Clears the data structure cache.
-   * @param id - The ID of the specific data structure to clear. If not provided, clears all.
-   */
-  public clearDataStructureCache(id?: string) {
-    if (id) {
-      this.dataStructureCache.clear(id);
-      this.dataStructuresMap.delete(id);
-    } else {
-      this.dataStructureCache.clearAll();
-      this.dataStructuresMap.clear();
-    }
-  }
-
-  /**
-   * Initializes the DatasetManager with index patterns.
-   * @param indexPatterns - The index patterns contract.
-   */
-  public init = async (indexPatterns: IndexPatternsContract) => {
-    this.indexPatterns = indexPatterns;
-    this.defaultDataset = await this.fetchDefaultDataset();
-  };
-
-  /**
-   * Gets the default dataset.
-   * @returns The default dataset, or undefined if not set.
-   */
-  public getDefaultDataset = () => {
-    return this.defaultDataset;
-  };
-
-  /**
-   * Fetches the default dataset.
-   * @returns A promise that resolves to the default dataset, or undefined if not found.
-   */
-  public fetchDefaultDataset = async (): Promise<Dataset | undefined> => {
-    const defaultIndexPatternId = this.uiSettings.get('defaultIndex');
-    if (!defaultIndexPatternId || !this.indexPatterns) {
-      return undefined;
-    }
-
-    const indexPattern = await this.indexPatterns.get(defaultIndexPatternId);
-    if (!indexPattern || !indexPattern.id) {
-      return undefined;
-    }
-
-    const handler = this.datasetHandlers.get(DEFAULT_DATA.SET_TYPES.INDEX_PATTERN);
-    if (handler) {
-      const dataset = handler.toDataset([
-        {
-          id: indexPattern.id,
-          title: indexPattern.title,
-          type: DEFAULT_DATA.SET_TYPES.INDEX_PATTERN,
-        },
-      ]);
-      return { ...dataset, timeFieldName: indexPattern.timeFieldName };
-    }
-
-    return undefined;
-  };
-}
-
-export type DatasetContract = PublicMethodsOf<DatasetManager>;
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/index.ts b/src/plugins/data/public/query/query_string/dataset_manager/index.ts
deleted file mode 100644
index c80f62eb39c..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/index.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-export * from './types';
-export { DatasetContract, DatasetManager } from './dataset_manager';
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/lib/index.ts b/src/plugins/data/public/query/query_string/dataset_manager/lib/index.ts
deleted file mode 100644
index 061b7724421..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/lib/index.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-export * from './index_handler';
-export * from './index_pattern_handler';
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/lib/index_handler.ts b/src/plugins/data/public/query/query_string/dataset_manager/lib/index_handler.ts
deleted file mode 100644
index ecf56b957ff..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/lib/index_handler.ts
+++ /dev/null
@@ -1,146 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { SavedObjectsClientContract } from 'opensearch-dashboards/public';
-import { map } from 'rxjs/operators';
-import { DEFAULT_DATA, DataStructure, DatasetField, Dataset } from '../../../../../common';
-import { DatasetTypeConfig } from '../types';
-import { getSearchService, getIndexPatterns } from '../../../../services';
-
-const INDEX_INFO = {
-  ID: DEFAULT_DATA.SET_TYPES.INDEX,
-  TITLE: 'Indexes',
-  ICON: 'logoOpenSearch',
-  LOCAL_DATASOURCE: {
-    id: '',
-    title: 'Local Cluster',
-    type: 'DATA_SOURCE',
-  },
-};
-
-export const indexHandlerConfig: DatasetTypeConfig = {
-  id: DEFAULT_DATA.SET_TYPES.INDEX,
-  title: 'Indexes',
-  meta: {
-    icon: { type: 'logoOpenSearch' },
-    tooltip: 'OpenSearch Indexes',
-  },
-
-  toDataset: (path: DataStructure[]): Dataset => {
-    const index = path[path.length - 1];
-    const dataSource = path.find((ds) => ds.type === 'DATA_SOURCE');
-
-    return {
-      id: index.id,
-      title: index.title,
-      type: DEFAULT_DATA.SET_TYPES.INDEX,
-      dataSource: dataSource
-        ? {
-            id: dataSource.id,
-            title: dataSource.title,
-            type: dataSource.type,
-          }
-        : INDEX_INFO.LOCAL_DATASOURCE,
-    };
-  },
-
-  fetch: async (
-    savedObjects: SavedObjectsClientContract,
-    path: DataStructure[]
-  ): Promise<DataStructure> => {
-    const dataStructure = path[path.length - 1];
-    switch (dataStructure.type) {
-      case 'DATA_SOURCE': {
-        const indices = await fetchIndices(dataStructure);
-        return {
-          ...dataStructure,
-          hasNext: true,
-          columnHeader: 'Indexes',
-          children: indices.map((indexName) => ({
-            id: `${dataStructure.id}::${indexName}`,
-            title: indexName,
-            type: 'INDEX',
-          })),
-        };
-      }
-
-      default: {
-        const dataSources = await fetchDataSources(savedObjects);
-        return {
-          ...dataStructure,
-          columnHeader: 'Cluster',
-          hasNext: false,
-          children: dataSources,
-        };
-      }
-    }
-  },
-
-  fetchFields: async (dataset: Dataset): Promise<DatasetField[]> => {
-    const fields = await getIndexPatterns().getFieldsForWildcard({
-      pattern: dataset.title,
-      dataSourceId: dataset.dataSource?.id,
-    });
-    return fields.map((field: any) => ({
-      name: field.name,
-      type: field.type,
-    }));
-  },
-
-  supportedLanguages: async (): Promise<string[]> => {
-    return ['SQL', 'PPL'];
-  },
-};
-
-const fetchDataSources = async (client: SavedObjectsClientContract) => {
-  const resp = await client.find<any>({
-    type: 'data-source',
-    perPage: 10000,
-  });
-  const dataSources: DataStructure[] = [INDEX_INFO.LOCAL_DATASOURCE];
-  return dataSources.concat(
-    resp.savedObjects.map((savedObject) => ({
-      id: savedObject.id,
-      title: savedObject.attributes.title,
-      type: 'DATA_SOURCE',
-    }))
-  );
-};
-
-const fetchIndices = async (dataStructure: DataStructure): Promise<string[]> => {
-  const search = getSearchService();
-  const buildSearchRequest = () => ({
-    params: {
-      ignoreUnavailable: true,
-      expand_wildcards: 'all',
-      index: '*',
-      body: {
-        size: 0,
-        aggs: {
-          indices: {
-            terms: {
-              field: '_index',
-              size: 100,
-            },
-          },
-        },
-      },
-    },
-    dataSourceId: dataStructure.id,
-  });
-
-  const searchResponseToArray = (response: any) => {
-    const { rawResponse } = response;
-    return rawResponse.aggregations
-      ? rawResponse.aggregations.indices.buckets.map((bucket: { key: any }) => bucket.key)
-      : [];
-  };
-
-  return search
-    .getDefaultSearchInterceptor()
-    .search(buildSearchRequest())
-    .pipe(map(searchResponseToArray))
-    .toPromise();
-};
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/lib/index_pattern_handler.ts b/src/plugins/data/public/query/query_string/dataset_manager/lib/index_pattern_handler.ts
deleted file mode 100644
index 37a7d738bb0..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/lib/index_pattern_handler.ts
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { SavedObjectsClientContract } from 'opensearch-dashboards/public';
-import { DEFAULT_DATA, DataStructure, DatasetField, Dataset } from '../../../../../common';
-import { DatasetTypeConfig } from '../types';
-import { getIndexPatterns } from '../../../../services';
-
-export const indexPatternHandlerConfig: DatasetTypeConfig = {
-  id: DEFAULT_DATA.SET_TYPES.INDEX_PATTERN,
-  title: 'Index Patterns',
-  meta: {
-    icon: { type: 'indexPatternApp' },
-    tooltip: 'OpenSearch Index Patterns',
-  },
-
-  toDataset: (path: DataStructure[]): Dataset => {
-    const pattern = path[path.length - 1];
-    return {
-      id: pattern.id,
-      title: pattern.title,
-      type: DEFAULT_DATA.SET_TYPES.INDEX_PATTERN,
-      dataSource: pattern.parent
-        ? {
-            id: pattern.parent.id,
-            title: pattern.parent.title,
-            type: pattern.parent.type,
-          }
-        : undefined,
-    };
-  },
-
-  fetch: async (
-    savedObjects: SavedObjectsClientContract,
-    path: DataStructure[]
-  ): Promise<DataStructure> => {
-    const dataStructure = path[path.length - 1];
-    const indexPatterns = await fetchIndexPatterns(savedObjects);
-    return {
-      ...dataStructure,
-      groupName: 'Index patterns',
-      children: indexPatterns,
-      hasNext: false,
-    };
-  },
-
-  fetchFields: async (dataset: Dataset): Promise<DatasetField[]> => {
-    const indexPattern = await getIndexPatterns().get(dataset.id);
-    return indexPattern.fields.map((field: any) => ({
-      name: field.name,
-      type: field.type,
-    }));
-  },
-
-  supportedLanguages: async (): Promise<string[]> => {
-    return ['SQL', 'PPL', 'KQL', 'Lucene'];
-  },
-};
-
-const fetchIndexPatterns = async (client: SavedObjectsClientContract): Promise<DataStructure[]> => {
-  const resp = await client.find<any>({
-    type: 'index-pattern',
-    fields: ['title'],
-    perPage: 10000,
-  });
-  return resp.savedObjects.map((savedObject) => ({
-    id: savedObject.id,
-    title: savedObject.attributes.title,
-    type: DEFAULT_DATA.SET_TYPES.INDEX_PATTERN,
-    isLeaf: true,
-  }));
-};
diff --git a/src/plugins/data/public/query/query_string/dataset_manager/types.ts b/src/plugins/data/public/query/query_string/dataset_manager/types.ts
deleted file mode 100644
index 0d7bf37703c..00000000000
--- a/src/plugins/data/public/query/query_string/dataset_manager/types.ts
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-import { SavedObjectsClientContract } from 'opensearch-dashboards/public';
-import { EuiIconProps } from '@elastic/eui';
-import { Dataset, DatasetField, DataStructure } from '../../../../common';
-
-/**
- * Configuration for handling dataset operations.
- */
-export interface DatasetTypeConfig {
-  /** Unique identifier for the dataset handler */
-  id: string;
-  /** Human-readable title for the dataset type */
-  title: string;
-  /** Metadata for UI representation */
-  meta: {
-    /** Icon to represent the dataset type */
-    icon: EuiIconProps;
-    /** Optional tooltip text */
-    tooltip?: string;
-  };
-  /**
-   * Converts a DataStructure to a Dataset.
-   * @param {DataStructure} dataStructure - The data structure to convert.
-   * @returns {Dataset} Dataset.
-   */
-  toDataset: (path: DataStructure[]) => Dataset;
-  /**
-   * Fetches child options for a given DataStructure.
-   * @param {SavedObjectsClientContract} client - The saved objects client.
-   * @param {DataStructure} dataStructure - The parent DataStructure.
-   * @returns {Promise<DatasetHandlerFetchResponse>} A promise that resolves to a DatasetHandlerFetchResponse.
-   */
-  fetch: (client: SavedObjectsClientContract, path: DataStructure[]) => Promise<DataStructure>;
-  /**
-   * Fetches fields for the dataset.
-   * @returns {Promise<DatasetField[]>} A promise that resolves to an array of DatasetFields.
-   */
-  fetchFields: (dataset: Dataset) => Promise<DatasetField[]>;
-  /**
-   * Retrieves the supported query languages for this dataset type.
-   * @returns {Promise<string[]>} A promise that resolves to an array of supported language names.
-   */
-  supportedLanguages: () => Promise<string[]>;
-}
diff --git a/src/plugins/data/public/query/query_string/dataset_service/dataset_service.ts b/src/plugins/data/public/query/query_string/dataset_service/dataset_service.ts
index 59e8138726a..0f152784f91 100644
--- a/src/plugins/data/public/query/query_string/dataset_service/dataset_service.ts
+++ b/src/plugins/data/public/query/query_string/dataset_service/dataset_service.ts
@@ -4,13 +4,7 @@
  */
 
 import { CoreStart, SavedObjectsClientContract } from 'opensearch-dashboards/public';
-import {
-  Dataset,
-  UI_SETTINGS,
-  DataStructure,
-  IndexPatternSpec,
-  DEFAULT_DATA,
-} from '../../../../common';
+import { Dataset, DataStructure, IndexPatternSpec, DEFAULT_DATA } from '../../../../common';
 import { getIndexPatterns } from '../../../services';
 import { DatasetTypeConfig } from './types';
 import { indexPatternTypeConfig, indexTypeConfig } from './lib';
@@ -32,7 +26,6 @@ export class DatasetService {
   }
 
   public async init(): Promise<void> {
-    if (!this.uiSettings.get(UI_SETTINGS.QUERY_ENHANCEMENTS_ENABLED)) return;
     this.defaultDataset = await this.fetchDefaultDataset();
   }
 
@@ -44,6 +37,10 @@ export class DatasetService {
     return this.typesRegistry.get(type);
   }
 
+  public getTypes(): DatasetTypeConfig[] {
+    return Array.from(this.typesRegistry.values());
+  }
+
   public getDefault(): Dataset | undefined {
     return this.defaultDataset;
   }
@@ -79,10 +76,6 @@ export class DatasetService {
     return type.fetch(savedObjects, path);
   }
 
-  public getTypes(): string[] {
-    return Array.from(this.typesRegistry.keys());
-  }
-
   private async fetchDefaultDataset(): Promise<Dataset | undefined> {
     const defaultIndexPatternId = this.uiSettings.get('defaultIndex');
     if (!defaultIndexPatternId) {
diff --git a/src/plugins/data/public/query/query_string/dataset_service/lib/index_pattern_type.ts b/src/plugins/data/public/query/query_string/dataset_service/lib/index_pattern_type.ts
index 6e4e6106291..c5f44445695 100644
--- a/src/plugins/data/public/query/query_string/dataset_service/lib/index_pattern_type.ts
+++ b/src/plugins/data/public/query/query_string/dataset_service/lib/index_pattern_type.ts
@@ -55,7 +55,7 @@ export const indexPatternTypeConfig: DatasetTypeConfig = {
   },
 
   supportedLanguages: (): string[] => {
-    return ['SQL', 'PPL', 'kuery', 'lucene'];
+    return ['SQL', 'PPL', 'DQL', 'Lucene'];
   },
 };
 
@@ -69,6 +69,5 @@ const fetchIndexPatterns = async (client: SavedObjectsClientContract): Promise<D
     id: savedObject.id,
     title: savedObject.attributes.title,
     type: DEFAULT_DATA.SET_TYPES.INDEX_PATTERN,
-    hasNext: true,
   }));
 };
diff --git a/src/plugins/data/public/query/query_string/dataset_service/lib/index_type.ts b/src/plugins/data/public/query/query_string/dataset_service/lib/index_type.ts
index 680d3f081b1..5e3622a2ed0 100644
--- a/src/plugins/data/public/query/query_string/dataset_service/lib/index_type.ts
+++ b/src/plugins/data/public/query/query_string/dataset_service/lib/index_type.ts
@@ -53,7 +53,7 @@ export const indexTypeConfig: DatasetTypeConfig = {
         const indices = await fetchIndices(dataStructure);
         return {
           ...dataStructure,
-          hasNext: true,
+          hasNext: false,
           columnHeader: 'Indexes',
           children: indices.map((indexName) => ({
             id: `${dataStructure.id}::${indexName}`,
@@ -68,7 +68,7 @@ export const indexTypeConfig: DatasetTypeConfig = {
         return {
           ...dataStructure,
           columnHeader: 'Cluster',
-          hasNext: false,
+          hasNext: true,
           children: dataSources,
         };
       }
diff --git a/src/plugins/data/public/query/query_string/language_service/language_service.ts b/src/plugins/data/public/query/query_string/language_service/language_service.ts
index 9c2e897097c..6e6e60411b6 100644
--- a/src/plugins/data/public/query/query_string/language_service/language_service.ts
+++ b/src/plugins/data/public/query/query_string/language_service/language_service.ts
@@ -35,8 +35,8 @@ export class LanguageService {
     return this.languages.get(language);
   }
 
-  public getLanguages(): string[] {
-    return Array.from(this.languages.keys());
+  public getLanguages(): LanguageConfig[] {
+    return Array.from(this.languages.values());
   }
 
   public getDefaultLanguage(): LanguageConfig {
diff --git a/src/plugins/data/public/query/query_string/query_string_manager.mock.ts b/src/plugins/data/public/query/query_string/query_string_manager.mock.ts
index df19bce5898..45e4fbc6913 100644
--- a/src/plugins/data/public/query/query_string/query_string_manager.mock.ts
+++ b/src/plugins/data/public/query/query_string/query_string_manager.mock.ts
@@ -28,38 +28,7 @@
  * under the License.
  */
 
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Any modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-/*
- * Licensed to Elasticsearch B.V. under one or more contributor
- * license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright
- * ownership. Elasticsearch B.V. licenses this file to you under
- * the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
 import { QueryStringContract } from '.';
-// import { datasetManagerMock } from './dataset_manager/dataset_manager.mock';
 
 const createSetupContractMock = () => {
   const queryStringManagerMock: jest.Mocked<QueryStringContract> = {
@@ -73,14 +42,9 @@ const createSetupContractMock = () => {
     getQueryHistory: jest.fn(),
     clearQueryHistory: jest.fn(),
     changeQueryHistory: jest.fn(),
-    getDatasetManager: jest.fn(),
-    initDataset: jest.fn(),
-    registerType: jest.fn(),
-    getDatasetType: jest.fn(),
-    getDatasetTypes: jest.fn(),
-    getLanguage: jest.fn(),
-    getLanguages: jest.fn(),
-    registerLanguage: jest.fn(),
+    getInitialQuery: jest.fn(),
+    getDatasetService: jest.fn(),
+    getLanguageService: jest.fn(),
   };
   return queryStringManagerMock;
 };
diff --git a/src/plugins/data/public/query/query_string/query_string_manager.ts b/src/plugins/data/public/query/query_string/query_string_manager.ts
index 1fa6641dd0a..7760e621ed3 100644
--- a/src/plugins/data/public/query/query_string/query_string_manager.ts
+++ b/src/plugins/data/public/query/query_string/query_string_manager.ts
@@ -33,14 +33,12 @@ import { skip } from 'rxjs/operators';
 import { CoreStart } from 'opensearch-dashboards/public';
 import { Dataset, DataStorage, Query, TimeRange, UI_SETTINGS } from '../../../common';
 import { createHistory, QueryHistory } from './query_history';
-import { DatasetContract } from './dataset_manager';
-import { DatasetService, DatasetServiceContract, DatasetTypeConfig } from './dataset_service';
-import { LanguageConfig, LanguageService, LanguageServiceContract } from './language_service';
+import { DatasetService, DatasetServiceContract } from './dataset_service';
+import { LanguageService, LanguageServiceContract } from './language_service';
 
 export class QueryStringManager {
   private query$: BehaviorSubject<Query>;
   private queryHistory: QueryHistory;
-  private datasetManager!: DatasetContract;
   private datasetService!: DatasetServiceContract;
   private languageService!: LanguageServiceContract;
 
@@ -50,7 +48,6 @@ export class QueryStringManager {
   ) {
     this.query$ = new BehaviorSubject<Query>(this.getDefaultQuery());
     this.queryHistory = createHistory({ storage });
-    // this.datasetManager = new DatasetManager(uiSettings);
     this.datasetService = new DatasetService(uiSettings);
     this.languageService = new LanguageService(uiSettings);
   }
@@ -135,31 +132,26 @@ export class QueryStringManager {
   public changeQueryHistory(listener: (reqs: any[]) => void) {
     return this.queryHistory.change(listener);
   }
-  /**
-   * TODO: verify if we want to just access the dataset manager directly or access each function
-   */
-  public getDatasetManager = () => {
-    return this.datasetManager;
-  };
 
-  public initDataset = async () => {
-    await this.datasetService.init();
+  public getDatasetService = () => {
+    return this.datasetService;
   };
 
-  public registerType = (type: DatasetTypeConfig) => {
-    this.datasetService.registerType(type);
+  public getLanguageService = () => {
+    return this.languageService;
   };
 
-  public getDatasetType = (type: string) => {
-    return this.datasetService.getType(type);
-  };
-
-  public getDatasetTypes = () => {
-    return this.datasetService.getTypes();
-  };
+  public getInitialQuery = () => {
+    const curQuery = this.query$.getValue();
+    const language = this.languageService.getLanguage(curQuery.language);
+    const dataset = curQuery.dataset;
+    const input = language?.searchBar?.queryStringInput?.initialValue || '';
 
-  public getLanguage = (language: string) => {
-    return this.languageService.getLanguage(language);
+    return {
+      query: input || input.replace('<data_source>', dataset?.title ?? ''),
+      language: curQuery.language,
+      dataset: curQuery.dataset,
+    };
   };
 
   private getDefaultLanguage() {
@@ -168,14 +160,6 @@ export class QueryStringManager {
       this.uiSettings.get(UI_SETTINGS.SEARCH_QUERY_LANGUAGE)
     );
   }
-
-  public getLanguages = () => {
-    return this.languageService.getLanguages();
-  };
-
-  public registerLanguage = (languageConfig: LanguageConfig) => {
-    this.languageService.registerLanguage(languageConfig);
-  };
 }
 
 export type QueryStringContract = PublicMethodsOf<QueryStringManager>;
diff --git a/src/plugins/data/public/query/state_sync/create_global_query_observable.ts b/src/plugins/data/public/query/state_sync/create_global_query_observable.ts
index 04f52daad90..8abcb3ece18 100644
--- a/src/plugins/data/public/query/state_sync/create_global_query_observable.ts
+++ b/src/plugins/data/public/query/state_sync/create_global_query_observable.ts
@@ -52,7 +52,6 @@ export function createQueryStateObservable({
       refreshInterval: timefilter.getRefreshInterval(),
       filters: filterManager.getFilters(),
       query: queryString.getQuery(),
-      dataset: queryString.getDatasetManager().getDataset(),
     });
 
     let currentChange: QueryStateChange = {};
@@ -61,13 +60,6 @@ export function createQueryStateObservable({
         currentChange.query = true;
         state.set({ ...state.get(), query: queryString.getQuery() });
       }),
-      queryString
-        .getDatasetManager()
-        .getUpdates$()
-        .subscribe(() => {
-          currentChange.dataset = true;
-          state.set({ ...state.get(), dataset: queryString.getDatasetManager().getDataset() });
-        }),
       timefilter.getTimeUpdate$().subscribe(() => {
         currentChange.time = true;
         state.set({ ...state.get(), time: timefilter.getTime() });
diff --git a/src/plugins/data/public/search/search_service.ts b/src/plugins/data/public/search/search_service.ts
index d07f63cbbba..1b5323d5fda 100644
--- a/src/plugins/data/public/search/search_service.ts
+++ b/src/plugins/data/public/search/search_service.ts
@@ -136,18 +136,18 @@ export class SearchService implements Plugin<ISearchSetup, ISearchStart> {
   ): ISearchStart {
     const search = ((request, options) => {
       const queryStringManager = getQueryService().queryString;
-      const languageId = queryStringManager.getQuery().language;
-      const selectedLanguage = queryStringManager.getLanguage(languageId);
-      getUiService().Settings.setUiOverridesByUserQueryLanguage(languageId);
+      const language = queryStringManager.getQuery().language;
+      const languageConfig = queryStringManager.getLanguageService().getLanguage(language);
+      getUiService().Settings.setUiOverridesByUserQueryLanguage(language);
       const isEnhancedEnabled = uiSettings.get(UI_SETTINGS.QUERY_ENHANCEMENTS_ENABLED);
 
-      if (selectedLanguage) {
+      if (languageConfig) {
         if (!isEnhancedEnabled) {
           notifications.toasts.addWarning(
-            `Query enhancements are disabled. Please enable to use: ${selectedLanguage.id}.`
+            `Query enhancements are disabled. Please enable to use: ${languageConfig.id}.`
           );
         }
-        return selectedLanguage.search.search(request, options);
+        return languageConfig.search.search(request, options);
       }
       return this.defaultSearchInterceptor.search(request, options);
     }) as ISearchGeneric;
diff --git a/src/plugins/data/public/ui/dataset_selector/__mocks__/utils.ts b/src/plugins/data/public/ui/dataset_selector/__mocks__/utils.ts
index e373f33c4ae..68fc16ed4b1 100644
--- a/src/plugins/data/public/ui/dataset_selector/__mocks__/utils.ts
+++ b/src/plugins/data/public/ui/dataset_selector/__mocks__/utils.ts
@@ -3,347 +3,341 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import {
-  Dataset,
-  DatasetManager,
-  DatasetTypeConfig,
-  DataSource,
-  DataStructure,
-} from '../../../../common/datasets';
-
-interface DatasetVariations {
-  dataSourceTypes: string[];
-  dataSetTypes: string[];
-  timeFields: string[];
-}
-
-export function generateRandomDatasets(count: number, variations: DatasetVariations): Dataset[] {
-  const datasets: Dataset[] = [];
-
-  for (let i = 0; i < count; i++) {
-    const dataSource: DataSource = {
-      id: `ds-${Math.random().toString(36).substr(2, 9)}`,
-      title: `Data Source ${i + 1}`,
-      type:
-        variations.dataSourceTypes[Math.floor(Math.random() * variations.dataSourceTypes.length)],
-    };
-
-    const dataset: Dataset = {
-      id: `dataset-${Math.random().toString(36).substr(2, 9)}`,
-      title: `Dataset ${i + 1}`,
-      type: variations.dataSetTypes[Math.floor(Math.random() * variations.dataSetTypes.length)],
-      timeFieldName:
-        variations.timeFields[Math.floor(Math.random() * variations.timeFields.length)],
-      dataSource,
-    };
-
-    datasets.push(dataset);
-  }
-
-  return datasets;
-}
-
-class MockDatasetManager implements DatasetManager {
-  private types: {
-    [key: string]: DatasetTypeConfig;
-  } = {};
-
-  private dataset?: Dataset;
-  private recentDatasets: Dataset[] = [];
-
-  constructor() {
-    this.registerType({
-      id: 'index-pattern',
-      title: 'Index Pattern',
-      getOptions: this.mockGetIndexPatternOptions,
-      getDataset: this.mockGetIndexPatternDataset,
-      getFields: this.mockGetIndexPatternFields,
-      config: {
-        supportedLanguages: ['DQL', 'lucene'],
-        icon: {
-          type: 'indexPatternApp',
-        },
-      },
-    });
-
-    this.registerType({
-      id: 'indices',
-      title: 'Indices',
-      getOptions: this.mockGetIndicesOptions,
-      getDataset: this.mockGetIndicesDataset,
-      getFields: this.mockGetIndicesFields,
-      config: {
-        supportedLanguages: ['DQL', 'lucene'],
-        icon: {
-          type: 'logoOpenSearch',
-        },
-        hasTimeField: true,
-      },
-    });
-
-    this.registerType({
-      id: 's3',
-      title: 'S3',
-      getOptions: this.mockGetS3Options,
-      getDataset: this.mockGetS3Dataset,
-      getFields: this.mockGetS3Fields,
-      config: {
-        supportedLanguages: ['SQL'],
-        icon: {
-          type: 'logoAWS',
-        },
-        hasTimeField: false,
-      },
-    });
-  }
-
-  registerType = (props: DatasetTypeConfig) => {
-    this.types[props.id] = props;
-  };
-
-  getTypes = () => {
-    return Object.values(this.types);
-  };
-
-  getType = (type: string) => {
-    return this.types[type];
-  };
-
-  getDataSet = () => {
-    return this.dataset;
-  };
-
-  setDataSet = (dataset: Dataset) => {
-    this.dataset = dataset;
-    // Store the top 10 recently used
-    this.recentDatasets = [dataset, ...this.recentDatasets].slice(0, 10);
-  };
-
-  getRecentlyUsed = () => {
-    return this.recentDatasets;
-  };
-
-  private mockGetIndexPatternOptions = async (path?: DataStructure[]) => {
-    const lastOption = path?.[path.length - 1];
-
-    if (lastOption?.id !== 'index-pattern') {
-      return {
-        options: [],
-        columnHeader: 'Index patterns',
-      };
-    }
-    const mockData: DataStructure[] = [
-      { id: 'pattern1', title: 'logs-*', type: 'index-pattern' },
-      { id: 'pattern2', title: 'metrics-*', type: 'index-pattern' },
-      { id: 'pattern3', title: 'events-*', type: 'index-pattern' },
-    ];
-
-    return {
-      options: mockData,
-      columnHeader: 'Index patterns',
-    };
-  };
-
-  private mockGetIndexPatternDataset = (path: DataStructure[]) => {
-    const lastOption = path?.[path.length - 1];
-
-    return {
-      id: lastOption?.id,
-      title: lastOption?.title,
-      type: 'index-pattern',
-      timeFieldName: 'timestamp',
-      dataSource: {
-        id: 'main-cluster',
-        title: 'Main OpenSearch Cluster',
-        type: 'OPENSEARCH',
-      },
-    };
-  };
-
-  private mockGetIndexPatternFields = async (dataset: Dataset) => {
-    return [
-      {
-        name: 'timestamp',
-        type: 'date',
-      },
-      {
-        name: 'bytes',
-        type: 'number',
-      },
-      {
-        name: 'cpu',
-        type: 'number',
-      },
-      {
-        name: 'memory',
-        type: 'number',
-      },
-      {
-        name: 'log',
-        type: 'string',
-      },
-    ];
-  };
-
-  private mockGetIndicesOptions = async (path?: DataStructure[]) => {
-    const option = path?.[path.length - 1];
-    if (option?.type === 'indices') {
-      // First level: List of clusters
-      const mockClusters: DataStructure[] = [
-        { id: 'cluster1', title: 'Production Cluster', type: 'cluster' },
-        { id: 'cluster2', title: 'Development Cluster', type: 'cluster' },
-        { id: 'cluster3', title: 'Testing Cluster', type: 'cluster' },
-      ];
-
-      return {
-        options: mockClusters,
-        isLoadable: true,
-        columnHeader: 'Clusters',
-      };
-    } else if (option?.type === 'cluster') {
-      // Second level: List of indices within the selected cluster
-      const mockIndices: DataStructure[] = [
-        { id: `${option.id}-index1`, title: `${option.title}-logs-2023.05`, type: 'index' },
-        { id: `${option.id}-index2`, title: `${option.title}-metrics-2023.05`, type: 'index' },
-        { id: `${option.id}-index3`, title: `${option.title}-events-2023.05`, type: 'index' },
-      ];
-
-      return {
-        options: mockIndices,
-        columnHeader: 'Indices',
-      };
-    }
-
-    // If we reach here, it's an unexpected state
-    return {
-      options: [],
-      columnHeader: 'Indices',
-    };
-  };
-
-  private mockGetIndicesDataset = (path: DataStructure[]) => {
-    const option = path?.[path.length - 1];
-
-    return {
-      id: option?.id,
-      title: option?.title,
-      type: 'indices',
-      timeFieldName: 'timestamp',
-      dataSource: {
-        id: 'main-cluster',
-        title: 'Main OpenSearch Cluster',
-        type: 'OPENSEARCH',
-      },
-    };
-  };
-
-  private mockGetIndicesFields = async (dataset: Dataset) => {
-    return [
-      {
-        name: 'timestamp',
-        type: 'date',
-      },
-      {
-        name: 'bytes',
-        type: 'number',
-      },
-      {
-        name: 'cpu',
-        type: 'number',
-      },
-      {
-        name: 'memory',
-        type: 'number',
-      },
-      {
-        name: 'log',
-        type: 'string',
-      },
-    ];
-  };
-
-  private mockGetS3Options = async (path?: DataStructure[]) => {
-    const lastOption = path?.[path.length - 1];
-
-    if (!lastOption || lastOption.type === 's3') {
-      // First level: Connections (instantaneous)
-      const mockConnections: DataStructure[] = [
-        { id: 'conn1', title: 'Production S3', type: 'connection' },
-        { id: 'conn2', title: 'Development S3', type: 'connection' },
-        { id: 'conn3', title: 'Testing S3', type: 'connection' },
-      ];
-
-      return {
-        options: mockConnections,
-        columnHeader: 'S3 Connections',
-        isLoadable: true,
-      };
-    } else if (lastOption.type === 'connection') {
-      // Second level: Databases (10s delay)
-      await new Promise((resolve) => setTimeout(resolve, 3000));
-
-      const mockDatabases: DataStructure[] = [
-        { id: `${lastOption.id}-db1`, title: 'Customer Data', type: 'database' },
-        { id: `${lastOption.id}-db2`, title: 'Product Catalog', type: 'database' },
-        { id: `${lastOption.id}-db3`, title: 'Sales Records', type: 'database' },
-      ];
-
-      return {
-        options: mockDatabases,
-        columnHeader: 'S3 Databases',
-        isLoadable: true,
-      };
-    } else if (lastOption.type === 'database') {
-      // Third level: Tables (10s delay)
-      await new Promise((resolve) => setTimeout(resolve, 3000));
-
-      const mockTables: DataStructure[] = [
-        { id: `${lastOption.id}-table1`, title: 'Users', type: 'table' },
-        { id: `${lastOption.id}-table2`, title: 'Orders', type: 'table' },
-        { id: `${lastOption.id}-table3`, title: 'Products', type: 'table' },
-      ];
-
-      return {
-        options: mockTables,
-        columnHeader: 'S3 Tables',
-        isLoadable: false,
-      };
-    }
-
-    return {
-      options: [],
-      columnHeader: 'S3',
-    };
-  };
-
-  private mockGetS3Dataset = (path: DataStructure[]) => {
-    const lastOption = path[path.length - 1];
-
-    return {
-      id: lastOption.id,
-      title: lastOption.title,
-      type: 's3',
-      dataSource: {
-        id: path[1].id, // Connection ID
-        title: path[1].title, // Connection Title
-        type: 'S3',
-      },
-    };
-  };
-
-  private mockGetS3Fields = async (dataset: Dataset) => {
-    // Simulate a delay for field fetching
-    await new Promise((resolve) => setTimeout(resolve, 5000));
-
-    return [
-      { name: 'id', type: 'string' },
-      { name: 'name', type: 'string' },
-      { name: 'created_at', type: 'date' },
-      { name: 'updated_at', type: 'date' },
-      { name: 'value', type: 'number' },
-    ];
-  };
-}
-
-// Export an instance of the mock manager
-export const mockDatasetManager = new MockDatasetManager();
+// import { Dataset, DataSource, DataStructure } from '../../../../common/datasets';
+
+// interface DatasetVariations {
+//   dataSourceTypes: string[];
+//   dataSetTypes: string[];
+//   timeFields: string[];
+// }
+
+// export function generateRandomDatasets(count: number, variations: DatasetVariations): Dataset[] {
+//   const datasets: Dataset[] = [];
+
+//   for (let i = 0; i < count; i++) {
+//     const dataSource: DataSource = {
+//       id: `ds-${Math.random().toString(36).substr(2, 9)}`,
+//       title: `Data Source ${i + 1}`,
+//       type:
+//         variations.dataSourceTypes[Math.floor(Math.random() * variations.dataSourceTypes.length)],
+//     };
+
+//     const dataset: Dataset = {
+//       id: `dataset-${Math.random().toString(36).substr(2, 9)}`,
+//       title: `Dataset ${i + 1}`,
+//       type: variations.dataSetTypes[Math.floor(Math.random() * variations.dataSetTypes.length)],
+//       timeFieldName:
+//         variations.timeFields[Math.floor(Math.random() * variations.timeFields.length)],
+//       dataSource,
+//     };
+
+//     datasets.push(dataset);
+//   }
+
+//   return datasets;
+// }
+
+// class MockDatasetManager implements DatasetManager {
+//   private types: {
+//     [key: string]: DatasetTypeConfig;
+//   } = {};
+
+//   private dataset?: Dataset;
+//   private recentDatasets: Dataset[] = [];
+
+//   constructor() {
+//     this.registerType({
+//       id: 'index-pattern',
+//       title: 'Index Pattern',
+//       getOptions: this.mockGetIndexPatternOptions,
+//       getDataset: this.mockGetIndexPatternDataset,
+//       getFields: this.mockGetIndexPatternFields,
+//       config: {
+//         supportedLanguages: ['DQL', 'lucene'],
+//         icon: {
+//           type: 'indexPatternApp',
+//         },
+//       },
+//     });
+
+//     this.registerType({
+//       id: 'indices',
+//       title: 'Indices',
+//       getOptions: this.mockGetIndicesOptions,
+//       getDataset: this.mockGetIndicesDataset,
+//       getFields: this.mockGetIndicesFields,
+//       config: {
+//         supportedLanguages: ['DQL', 'lucene'],
+//         icon: {
+//           type: 'logoOpenSearch',
+//         },
+//         hasTimeField: true,
+//       },
+//     });
+
+//     this.registerType({
+//       id: 's3',
+//       title: 'S3',
+//       getOptions: this.mockGetS3Options,
+//       getDataset: this.mockGetS3Dataset,
+//       getFields: this.mockGetS3Fields,
+//       config: {
+//         supportedLanguages: ['SQL'],
+//         icon: {
+//           type: 'logoAWS',
+//         },
+//         hasTimeField: false,
+//       },
+//     });
+//   }
+
+//   registerType = (props: DatasetTypeConfig) => {
+//     this.types[props.id] = props;
+//   };
+
+//   getTypes = () => {
+//     return Object.values(this.types);
+//   };
+
+//   getType = (type: string) => {
+//     return this.types[type];
+//   };
+
+//   getDataSet = () => {
+//     return this.dataset;
+//   };
+
+//   setDataSet = (dataset: Dataset) => {
+//     this.dataset = dataset;
+//     // Store the top 10 recently used
+//     this.recentDatasets = [dataset, ...this.recentDatasets].slice(0, 10);
+//   };
+
+//   getRecentlyUsed = () => {
+//     return this.recentDatasets;
+//   };
+
+//   private mockGetIndexPatternOptions = async (path?: DataStructure[]) => {
+//     const lastOption = path?.[path.length - 1];
+
+//     if (lastOption?.id !== 'index-pattern') {
+//       return {
+//         options: [],
+//         columnHeader: 'Index patterns',
+//       };
+//     }
+//     const mockData: DataStructure[] = [
+//       { id: 'pattern1', title: 'logs-*', type: 'index-pattern' },
+//       { id: 'pattern2', title: 'metrics-*', type: 'index-pattern' },
+//       { id: 'pattern3', title: 'events-*', type: 'index-pattern' },
+//     ];
+
+//     return {
+//       options: mockData,
+//       columnHeader: 'Index patterns',
+//     };
+//   };
+
+//   private mockGetIndexPatternDataset = (path: DataStructure[]) => {
+//     const lastOption = path?.[path.length - 1];
+
+//     return {
+//       id: lastOption?.id,
+//       title: lastOption?.title,
+//       type: 'index-pattern',
+//       timeFieldName: 'timestamp',
+//       dataSource: {
+//         id: 'main-cluster',
+//         title: 'Main OpenSearch Cluster',
+//         type: 'OPENSEARCH',
+//       },
+//     };
+//   };
+
+//   private mockGetIndexPatternFields = async (dataset: Dataset) => {
+//     return [
+//       {
+//         name: 'timestamp',
+//         type: 'date',
+//       },
+//       {
+//         name: 'bytes',
+//         type: 'number',
+//       },
+//       {
+//         name: 'cpu',
+//         type: 'number',
+//       },
+//       {
+//         name: 'memory',
+//         type: 'number',
+//       },
+//       {
+//         name: 'log',
+//         type: 'string',
+//       },
+//     ];
+//   };
+
+//   private mockGetIndicesOptions = async (path?: DataStructure[]) => {
+//     const option = path?.[path.length - 1];
+//     if (option?.type === 'indices') {
+//       // First level: List of clusters
+//       const mockClusters: DataStructure[] = [
+//         { id: 'cluster1', title: 'Production Cluster', type: 'cluster' },
+//         { id: 'cluster2', title: 'Development Cluster', type: 'cluster' },
+//         { id: 'cluster3', title: 'Testing Cluster', type: 'cluster' },
+//       ];
+
+//       return {
+//         options: mockClusters,
+//         isLoadable: true,
+//         columnHeader: 'Clusters',
+//       };
+//     } else if (option?.type === 'cluster') {
+//       // Second level: List of indices within the selected cluster
+//       const mockIndices: DataStructure[] = [
+//         { id: `${option.id}-index1`, title: `${option.title}-logs-2023.05`, type: 'index' },
+//         { id: `${option.id}-index2`, title: `${option.title}-metrics-2023.05`, type: 'index' },
+//         { id: `${option.id}-index3`, title: `${option.title}-events-2023.05`, type: 'index' },
+//       ];
+
+//       return {
+//         options: mockIndices,
+//         columnHeader: 'Indices',
+//       };
+//     }
+
+//     // If we reach here, it's an unexpected state
+//     return {
+//       options: [],
+//       columnHeader: 'Indices',
+//     };
+//   };
+
+//   private mockGetIndicesDataset = (path: DataStructure[]) => {
+//     const option = path?.[path.length - 1];
+
+//     return {
+//       id: option?.id,
+//       title: option?.title,
+//       type: 'indices',
+//       timeFieldName: 'timestamp',
+//       dataSource: {
+//         id: 'main-cluster',
+//         title: 'Main OpenSearch Cluster',
+//         type: 'OPENSEARCH',
+//       },
+//     };
+//   };
+
+//   private mockGetIndicesFields = async (dataset: Dataset) => {
+//     return [
+//       {
+//         name: 'timestamp',
+//         type: 'date',
+//       },
+//       {
+//         name: 'bytes',
+//         type: 'number',
+//       },
+//       {
+//         name: 'cpu',
+//         type: 'number',
+//       },
+//       {
+//         name: 'memory',
+//         type: 'number',
+//       },
+//       {
+//         name: 'log',
+//         type: 'string',
+//       },
+//     ];
+//   };
+
+//   private mockGetS3Options = async (path?: DataStructure[]) => {
+//     const lastOption = path?.[path.length - 1];
+
+//     if (!lastOption || lastOption.type === 's3') {
+//       // First level: Connections (instantaneous)
+//       const mockConnections: DataStructure[] = [
+//         { id: 'conn1', title: 'Production S3', type: 'connection' },
+//         { id: 'conn2', title: 'Development S3', type: 'connection' },
+//         { id: 'conn3', title: 'Testing S3', type: 'connection' },
+//       ];
+
+//       return {
+//         options: mockConnections,
+//         columnHeader: 'S3 Connections',
+//         isLoadable: true,
+//       };
+//     } else if (lastOption.type === 'connection') {
+//       // Second level: Databases (10s delay)
+//       await new Promise((resolve) => setTimeout(resolve, 3000));
+
+//       const mockDatabases: DataStructure[] = [
+//         { id: `${lastOption.id}-db1`, title: 'Customer Data', type: 'database' },
+//         { id: `${lastOption.id}-db2`, title: 'Product Catalog', type: 'database' },
+//         { id: `${lastOption.id}-db3`, title: 'Sales Records', type: 'database' },
+//       ];
+
+//       return {
+//         options: mockDatabases,
+//         columnHeader: 'S3 Databases',
+//         isLoadable: true,
+//       };
+//     } else if (lastOption.type === 'database') {
+//       // Third level: Tables (10s delay)
+//       await new Promise((resolve) => setTimeout(resolve, 3000));
+
+//       const mockTables: DataStructure[] = [
+//         { id: `${lastOption.id}-table1`, title: 'Users', type: 'table' },
+//         { id: `${lastOption.id}-table2`, title: 'Orders', type: 'table' },
+//         { id: `${lastOption.id}-table3`, title: 'Products', type: 'table' },
+//       ];
+
+//       return {
+//         options: mockTables,
+//         columnHeader: 'S3 Tables',
+//         isLoadable: false,
+//       };
+//     }
+
+//     return {
+//       options: [],
+//       columnHeader: 'S3',
+//     };
+//   };
+
+//   private mockGetS3Dataset = (path: DataStructure[]) => {
+//     const lastOption = path[path.length - 1];
+
+//     return {
+//       id: lastOption.id,
+//       title: lastOption.title,
+//       type: 's3',
+//       dataSource: {
+//         id: path[1].id, // Connection ID
+//         title: path[1].title, // Connection Title
+//         type: 'S3',
+//       },
+//     };
+//   };
+
+//   private mockGetS3Fields = async (dataset: Dataset) => {
+//     // Simulate a delay for field fetching
+//     await new Promise((resolve) => setTimeout(resolve, 5000));
+
+//     return [
+//       { name: 'id', type: 'string' },
+//       { name: 'name', type: 'string' },
+//       { name: 'created_at', type: 'date' },
+//       { name: 'updated_at', type: 'date' },
+//       { name: 'value', type: 'number' },
+//     ];
+//   };
+// }
+
+// // Export an instance of the mock manager
+// export const mockDatasetManager = new MockDatasetManager();
diff --git a/src/plugins/data/public/ui/dataset_selector/advanced_selector.tsx b/src/plugins/data/public/ui/dataset_selector/advanced_selector.tsx
index b7f80571b79..a319c9a376b 100644
--- a/src/plugins/data/public/ui/dataset_selector/advanced_selector.tsx
+++ b/src/plugins/data/public/ui/dataset_selector/advanced_selector.tsx
@@ -31,19 +31,21 @@ export const AdvancedSelector = ({
     {
       ...DEFAULT_DATA.STRUCTURES.ROOT,
       columnHeader: 'Select data',
-      hasNext: false,
-      children: queryString.getDatasetTypes().map((typeId) => {
-        const type = queryString.getDatasetType(typeId);
-        return {
-          id: type!.id,
-          title: type!.title,
-          type: type!.id,
-          meta: {
-            ...type!.meta,
-            type: DATA_STRUCTURE_META_TYPES.TYPE,
-          },
-        } as DataStructure;
-      }),
+      hasNext: true,
+      children: queryString
+        .getDatasetService()
+        .getTypes()
+        .map((type) => {
+          return {
+            id: type!.id,
+            title: type!.title,
+            type: type!.id,
+            meta: {
+              ...type!.meta,
+              type: DATA_STRUCTURE_META_TYPES.TYPE,
+            },
+          } as DataStructure;
+        }),
     },
   ]);
   const [selectedDataset, setSelectedDataset] = useState<BaseDataset | undefined>();
diff --git a/src/plugins/data/public/ui/dataset_selector/configurator.tsx b/src/plugins/data/public/ui/dataset_selector/configurator.tsx
index 5832fde784e..ce55fe331d3 100644
--- a/src/plugins/data/public/ui/dataset_selector/configurator.tsx
+++ b/src/plugins/data/public/ui/dataset_selector/configurator.tsx
@@ -36,7 +36,8 @@ export const Configurator = ({
   const queryService = getQueryService();
   const queryString = queryService.queryString;
   const indexPatternsService = getIndexPatterns();
-  const languages = queryString.getDatasetType(baseDataset.type)?.supportedLanguages() || [];
+  const languages =
+    queryString.getDatasetService().getType(baseDataset.type)?.supportedLanguages() || [];
 
   const [dataset, setDataset] = useState<Dataset>(baseDataset);
   const [fields, setFields] = useState<DatasetField[]>();
@@ -47,7 +48,8 @@ export const Configurator = ({
   useEffect(() => {
     const fetchFields = async () => {
       const datasetFields = await queryString
-        .getDatasetType(baseDataset.type)
+        .getDatasetService()
+        .getType(baseDataset.type)
         ?.fetchFields(baseDataset);
 
       setFields(datasetFields);
diff --git a/src/plugins/data/public/ui/dataset_selector/dataset_explorer.tsx b/src/plugins/data/public/ui/dataset_selector/dataset_explorer.tsx
index 8271efc631d..b17a38ae829 100644
--- a/src/plugins/data/public/ui/dataset_selector/dataset_explorer.tsx
+++ b/src/plugins/data/public/ui/dataset_selector/dataset_explorer.tsx
@@ -45,23 +45,23 @@ export const DatasetExplorer = ({
     const lastPathItem = newPath[newPath.length - 1];
     const nextPath = [...newPath, item];
 
-    const handler = queryString.getDatasetType(nextPath[1].id);
-    if (!handler) return;
+    const typeConfig = queryString.getDatasetService().getType(nextPath[1].id);
+    if (!typeConfig) return;
 
-    if (lastPathItem.hasNext) {
-      const dataset = handler!.toDataset(nextPath);
+    if (!lastPathItem.hasNext) {
+      const dataset = typeConfig!.toDataset(nextPath);
       setExplorerDataset(dataset as BaseDataset);
       return;
     }
 
     setLoading(true);
-    const nextDataStructure = await handler.fetch(savedObjects, nextPath);
+    const nextDataStructure = await typeConfig.fetch(savedObjects, nextPath);
     setLoading(false);
 
     setPath([...newPath, nextDataStructure]);
   };
 
-  const columnCount = !path[path.length - 1]?.hasNext ? path.length + 1 : path.length;
+  const columnCount = path[path.length - 1]?.hasNext ? path.length + 1 : path.length;
 
   return (
     <>
@@ -97,7 +97,7 @@ export const DatasetExplorer = ({
         >
           {path.map((current, index) => {
             const isLast = index === path.length - 1;
-            const isFinal = isLast && current.hasNext;
+            const isFinal = isLast && !current.hasNext;
             return (
               <div
                 key={current.id}
@@ -106,7 +106,7 @@ export const DatasetExplorer = ({
                 }`}
               >
                 <EuiTitle size="xxs" className="datasetExplorer__columnTitle">
-                  <h3>{current.hasNext}</h3>
+                  <h3>{current.columnHeader}</h3>
                 </EuiTitle>
                 <EuiSelectable
                   options={(current.children || []).map((child) => ({
@@ -145,7 +145,7 @@ export const DatasetExplorer = ({
               </div>
             );
           })}
-          {!!!path[path.length - 1]?.hasNext && <LoadingEmptyColumn isLoading={loading} />}
+          {!!path[path.length - 1]?.hasNext && <LoadingEmptyColumn isLoading={loading} />}
         </div>
       </EuiModalBody>
       <EuiModalFooter>
diff --git a/src/plugins/data/public/ui/dataset_selector/dataset_selector.tsx b/src/plugins/data/public/ui/dataset_selector/dataset_selector.tsx
index 3b2ec154188..1d04698d781 100644
--- a/src/plugins/data/public/ui/dataset_selector/dataset_selector.tsx
+++ b/src/plugins/data/public/ui/dataset_selector/dataset_selector.tsx
@@ -37,24 +37,24 @@ export const DatasetSelector = ({
   const closePopover = () => setIsOpen(false);
   const { overlays, savedObjects } = services;
 
-  const queryString = getQueryService().queryString;
+  const datasetService = getQueryService().queryString.getDatasetService();
 
   const datasetIcon =
-    queryString.getDatasetType(selectedDataset?.type || '')?.meta.icon.type || 'database';
+    datasetService.getType(selectedDataset?.type || '')?.meta.icon.type || 'database';
 
   useEffect(() => {
     const init = async () => {
       setDatasets(
         (
-          await queryString
-            .getDatasetType(DEFAULT_DATA.SET_TYPES.INDEX_PATTERN)
+          await datasetService
+            .getType(DEFAULT_DATA.SET_TYPES.INDEX_PATTERN)
             ?.fetch(savedObjects.client, [])!
         ).children || []
       );
     };
 
     init();
-  }, [queryString, savedObjects.client]);
+  }, [datasetService, savedObjects.client]);
 
   const options = useMemo(() => {
     const newOptions: EuiSelectableOption[] = [];
@@ -69,12 +69,12 @@ export const DatasetSelector = ({
         label: title,
         checked: id === selectedDataset?.id ? 'on' : undefined,
         key: id,
-        prepend: <EuiIcon type={queryString.getDatasetType(type)!.meta.icon.type} />,
+        prepend: <EuiIcon type={datasetService.getType(type)!.meta.icon.type} />,
       });
     });
 
     return newOptions;
-  }, [queryString, datasets, selectedDataset?.id]);
+  }, [datasets, selectedDataset?.id, datasetService]);
 
   // Handle option change
   const handleOptionChange = (newOptions: EuiSelectableOption[]) => {
diff --git a/src/plugins/data/public/ui/query_editor/language_selector.tsx b/src/plugins/data/public/ui/query_editor/language_selector.tsx
index 08886647822..647c087b0dc 100644
--- a/src/plugins/data/public/ui/query_editor/language_selector.tsx
+++ b/src/plugins/data/public/ui/query_editor/language_selector.tsx
@@ -3,11 +3,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-/*
- * Copyright OpenSearch Contributors
- * SPDX-License-Identifier: Apache-2.0
- */
-
 import React, { useState, useEffect } from 'react';
 import {
   PopoverAnchorPosition,
@@ -39,10 +34,11 @@ export const QueryLanguageSelector = (props: QueryLanguageSelectorProps) => {
   const [currentLanguage, setCurrentLanguage] = useState(props.query.language);
 
   const uiService = getUiService();
-  const queryService = getQueryService();
+  const queryString = getQueryService().queryString;
+  const languageService = queryString.getLanguageService();
 
   useEffect(() => {
-    const subscription = queryService.queryString.getUpdates$().subscribe((query: Query) => {
+    const subscription = queryString.getUpdates$().subscribe((query: Query) => {
       if (query.language !== currentLanguage) {
         setCurrentLanguage(query.language);
         props.onSelectLanguage(query.language);
@@ -52,7 +48,7 @@ export const QueryLanguageSelector = (props: QueryLanguageSelectorProps) => {
     return () => {
       subscription.unsubscribe();
     };
-  }, [queryService, currentLanguage, props.onSelectLanguage, props]);
+  }, [queryString, currentLanguage, props.onSelectLanguage, props]);
 
   const onButtonClick = () => {
     setPopover(!isPopoverOpen);
@@ -60,9 +56,7 @@ export const QueryLanguageSelector = (props: QueryLanguageSelectorProps) => {
 
   const languageOptions: Array<{ label: string; value: string }> = [];
 
-  const languages = queryService.queryString.getLanguages();
-  languages.forEach((languageId) => {
-    const language = queryService.queryString.getLanguage(languageId);
+  languageService.getLanguages().forEach((language) => {
     if (
       (language && props.appName && !language.supportedAppNames.includes(props.appName)) ||
       uiService.Settings.getUserQueryLanguageBlocklist().includes(language?.id)
@@ -84,8 +78,8 @@ export const QueryLanguageSelector = (props: QueryLanguageSelectorProps) => {
     uiService.Settings.setUserQueryLanguage(newLanguage);
 
     // Update the query in the QueryStringManager
-    const currentQuery = queryService.queryString.getQuery();
-    const input = queryService.queryString.getLanguage(newLanguage)?.searchBar?.queryStringInput
+    const currentQuery = queryString.getQuery();
+    const input = languageService.getLanguage(newLanguage)?.searchBar?.queryStringInput
       ?.initialValue;
 
     if (!input) return '';
@@ -94,7 +88,7 @@ export const QueryLanguageSelector = (props: QueryLanguageSelectorProps) => {
       currentQuery.dataset?.title ?? currentQuery.dataset?.title ?? ''
     );
 
-    queryService.queryString.setQuery({
+    queryString.setQuery({
       query: newQuery,
       language: newLanguage,
       dataset: currentQuery.dataset,
diff --git a/src/plugins/data/public/ui/query_editor/query_editor.tsx b/src/plugins/data/public/ui/query_editor/query_editor.tsx
index 508b9464f53..77a313184f0 100644
--- a/src/plugins/data/public/ui/query_editor/query_editor.tsx
+++ b/src/plugins/data/public/ui/query_editor/query_editor.tsx
@@ -86,7 +86,7 @@ export default class QueryEditorUI extends Component<Props, State> {
 
   public inputRef: monaco.editor.IStandaloneCodeEditor | null = null;
 
-  private queryService = getQueryService();
+  private queryString = getQueryService().queryString;
 
   private persistedLog: PersistedLog | undefined;
   private abortController?: AbortController;
@@ -181,7 +181,7 @@ export default class QueryEditorUI extends Component<Props, State> {
       body: JSON.stringify({ opt_in: languageId === 'kuery' }),
     });
 
-    const language = this.queryService.queryString.getLanguage(this.props.query.language);
+    const language = this.queryString.getLanguageService().getLanguage(this.props.query.language);
     const newQuery = {
       query: this.props.getQueryStringInitialValue?.(language!) ?? '',
       language: language?.id || languageId,
@@ -246,9 +246,9 @@ export default class QueryEditorUI extends Component<Props, State> {
   };
 
   private fetchIndexPattern = async () => {
-    const dataSetTitle = this.queryService.queryString.getDatasetManager().getDataset()?.title;
-    if (!dataSetTitle) return undefined;
-    return getIndexPatterns().getByTitle(dataSetTitle);
+    const dataset = this.queryString.getQuery().dataset;
+    if (!dataset) return undefined;
+    return getIndexPatterns().getByTitle(dataset.title);
   };
 
   provideCompletionItems = async (
diff --git a/src/plugins/data/public/ui/query_editor/query_editor_top_row.tsx b/src/plugins/data/public/ui/query_editor/query_editor_top_row.tsx
index e33a617f5d0..494f579efb4 100644
--- a/src/plugins/data/public/ui/query_editor/query_editor_top_row.tsx
+++ b/src/plugins/data/public/ui/query_editor/query_editor_top_row.tsx
@@ -22,11 +22,10 @@ import {
   withOpenSearchDashboards,
 } from '../../../../opensearch_dashboards_react/public';
 import { UI_SETTINGS } from '../../../common';
-import { getQueryLog, LanguageConfig, PersistedLog } from '../../query';
+import { getQueryLog, PersistedLog } from '../../query';
 import { Settings } from '../types';
 import { NoDataPopover } from './no_data_popover';
 import QueryEditorUI from './query_editor';
-import { useQueryStringManager } from '../search_bar/lib/use_query_string_manager';
 
 const QueryEditor = withOpenSearchDashboards(QueryEditorUI);
 
@@ -73,26 +72,20 @@ export default function QueryEditorTopRow(props: QueryEditorTopRowProps) {
       query: { queryString },
     },
   } = opensearchDashboards.services;
-  const {
-    query: { dataset },
-  } = useQueryStringManager({ queryStringManager: queryString });
 
-  const queryLanguageId = props.query && props.query.language;
-  const queryLanguage = queryString.getLanguage(queryLanguageId!) || null;
+  const language = props.query && props.query.language;
   const parsedQuery =
-    !queryLanguageId || isValidQuery(props.query)
-      ? props.query!
-      : { query: getQueryStringInitialValue(queryLanguage!), language: queryLanguageId! };
+    !language || isValidQuery(props.query) ? props.query! : queryString.getInitialQuery();
   if (!isEqual(parsedQuery?.query, props.query?.query)) {
     onQueryChange(parsedQuery);
     onSubmit({ query: parsedQuery, dateRange: getDateRange() });
   }
   const persistedLog: PersistedLog | undefined = React.useMemo(
     () =>
-      queryLanguage && uiSettings && storage && appName
-        ? getQueryLog(uiSettings!, storage, appName, queryLanguageId!)
+      language && uiSettings && storage && appName
+        ? getQueryLog(uiSettings!, storage, appName, language!)
         : undefined,
-    [queryLanguage, uiSettings, storage, appName, queryLanguageId]
+    [language, uiSettings, storage, appName]
   );
 
   function onClickSubmitButton(event: React.MouseEvent<HTMLButtonElement>) {
@@ -105,20 +98,22 @@ export default function QueryEditorTopRow(props: QueryEditorTopRowProps) {
 
   function getDateRange() {
     const defaultTimeSetting = uiSettings!.get(UI_SETTINGS.TIMEPICKER_TIME_DEFAULTS);
+    const languageConfig = queryString.getLanguageService().getLanguage(language!);
     return {
       from:
         props.dateRangeFrom ||
-        queryLanguage?.searchBar?.dateRange?.initialFrom ||
+        languageConfig?.searchBar?.dateRange?.initialFrom ||
         defaultTimeSetting.from,
       to:
         props.dateRangeTo ||
-        queryLanguage?.searchBar?.dateRange?.initialTo ||
+        languageConfig?.searchBar?.dateRange?.initialTo ||
         defaultTimeSetting.to,
     };
   }
 
   function onQueryChange(query: Query, dateRange?: TimeRange) {
-    if (queryLanguage && !isValidQuery(query)) return;
+    const languageConfig = queryString.getLanguageService().getLanguage(language!);
+    if (languageConfig && !isValidQuery(query)) return;
     props.onChange({
       query,
       dateRange: dateRange ?? getDateRange(),
@@ -195,21 +190,12 @@ export default function QueryEditorTopRow(props: QueryEditorTopRowProps) {
     if (query && query.query) return true;
   }
 
-  function getQueryStringInitialValue(language: LanguageConfig) {
-    const input = language?.searchBar?.queryStringInput?.initialValue;
-
-    if (!input) return '';
-
-    return input.replace('<data_source>', dataset?.title ?? dataset?.title ?? '');
-  }
-
   function renderQueryEditor() {
     if (!shouldRenderQueryEditor()) return;
     return (
       <EuiFlexItem>
         <QueryEditor
           disableAutoFocus={props.disableAutoFocus}
-          dataset={dataset}
           queryActions={props.prepend}
           query={parsedQuery}
           settings={props.settings!}
@@ -217,7 +203,6 @@ export default function QueryEditorTopRow(props: QueryEditorTopRowProps) {
           onChange={onQueryChange}
           onChangeQueryEditorFocus={onChangeQueryEditorFocus}
           onSubmit={onInputSubmit}
-          getQueryStringInitialValue={getQueryStringInitialValue}
           persistedLog={persistedLog}
           className="osdQueryEditor"
           dataTestSubj={props.dataTestSubj}
@@ -244,11 +229,10 @@ export default function QueryEditorTopRow(props: QueryEditorTopRowProps) {
   }
 
   function shouldRenderDatePicker(): boolean {
-    const languageId = queryString.getQuery().language;
-    const language = queryString.getLanguage(languageId);
+    const languageConfig = queryString.getLanguageService().getLanguage(language!);
     return Boolean(
-      (props.showDatePicker && (language?.searchBar?.showDatePicker ?? true)) ??
-        (props.showAutoRefreshOnly && (language?.searchBar?.showAutoRefreshOnly ?? true))
+      (props.showDatePicker && (languageConfig?.searchBar?.showDatePicker ?? true)) ??
+        (props.showAutoRefreshOnly && (languageConfig?.searchBar?.showAutoRefreshOnly ?? true))
     );
   }
 
diff --git a/src/plugins/data/public/ui/settings/settings.ts b/src/plugins/data/public/ui/settings/settings.ts
index 085f9397615..f5dd8f247f8 100644
--- a/src/plugins/data/public/ui/settings/settings.ts
+++ b/src/plugins/data/public/ui/settings/settings.ts
@@ -113,7 +113,7 @@ export class Settings {
   }
 
   setUiOverridesByUserQueryLanguage(languageId: string) {
-    const language = this.query.queryString.getLanguage(languageId);
+    const language = this.query.queryString.getLanguageService().getLanguage(languageId);
     if (language) {
       const { fields = {}, showDocLinks } = language;
       this.setUiOverrides({ fields, showDocLinks });
diff --git a/src/plugins/discover/public/application/view_components/canvas/top_nav.tsx b/src/plugins/discover/public/application/view_components/canvas/top_nav.tsx
index b24e7ba1c10..34cf98e1249 100644
--- a/src/plugins/discover/public/application/view_components/canvas/top_nav.tsx
+++ b/src/plugins/discover/public/application/view_components/canvas/top_nav.tsx
@@ -74,16 +74,16 @@ export const TopNav = ({ opts, showSaveQuery, isEnhancementsEnabled }: TopNavPro
     const initializeDataset = async () => {
       await data.indexPatterns.ensureDefaultIndexPattern();
       const defaultIndexPattern = await data.indexPatterns.getDefault();
-      const datasetManager = data.query.queryString.getDatasetManager();
-      datasetManager.fetchDefaultDataset();
-      const defaultDataset = datasetManager.getDefaultDataset();
+      // TODO: ROCKY do we need this?
+      // const queryString = data.query.queryString;
+      // const defaultDataset = queryString.getDatasetService().getDefault();
 
       if (!isMounted) return;
 
       setIndexPatterns(defaultIndexPattern ? [defaultIndexPattern] : undefined);
-      if (defaultDataset) {
-        datasetManager.setDataset(defaultDataset);
-      }
+      // if (defaultDataset) {
+      //   datasetManager.setDataset(defaultDataset);
+      // }
     };
 
     initializeDataset();
diff --git a/src/plugins/query_enhancements/public/plugin.tsx b/src/plugins/query_enhancements/public/plugin.tsx
index 58e2d2ae694..aead8dff3cc 100644
--- a/src/plugins/query_enhancements/public/plugin.tsx
+++ b/src/plugins/query_enhancements/public/plugin.tsx
@@ -16,7 +16,6 @@ import {
   QueryEnhancementsPluginStart,
   QueryEnhancementsPluginStartDependencies,
 } from './types';
-import { UI_SETTINGS } from '../common';
 import { LanguageConfig } from '../../data/public';
 import { s3TypeConfig } from './datasets';
 
@@ -40,6 +39,7 @@ export class QueryEnhancementsPlugin
     core: CoreSetup<QueryEnhancementsPluginStartDependencies>,
     { data }: QueryEnhancementsPluginSetupDependencies
   ): QueryEnhancementsPluginSetup {
+    const { queryString } = data.query;
     const pplSearchInterceptor = new PPLSearchInterceptor({
       toasts: core.notifications.toasts,
       http: core.http,
@@ -78,7 +78,7 @@ export class QueryEnhancementsPlugin
       showDocLinks: false,
       supportedAppNames: ['discover'],
     };
-    data.query.queryString.registerLanguage(pplLanguageConfig);
+    queryString.getLanguageService().registerLanguage(pplLanguageConfig);
 
     // Register SQL language
     const sqlLanguageConfig: LanguageConfig = {
@@ -99,7 +99,7 @@ export class QueryEnhancementsPlugin
       showDocLinks: false,
       supportedAppNames: ['discover'],
     };
-    data.query.queryString.registerLanguage(sqlLanguageConfig);
+    queryString.getLanguageService().registerLanguage(sqlLanguageConfig);
 
     data.__enhance({
       ui: {
@@ -107,7 +107,7 @@ export class QueryEnhancementsPlugin
       },
     });
 
-    data.query.queryString.registerType(s3TypeConfig);
+    queryString.getDatasetService().registerType(s3TypeConfig);
 
     return {};
   }