It looks like Elasticsearch is currently missing support for concurrent searching and that this is a major prospective optimization to reduce latency.

Digression: this is not the topic at hand but I personally consider the fork OpenSearch to be an historical tragedy of duplication of work and a segregation of improvements. What would be even more anti-utilitarist would be to blindly *ignore* each other advances towards making better search.

Lucene concurrent search APIs are probably among the most important feature/optimization currently not leveraged by Elasticsearch.
The fork OpenSearch has a [pull request](https://github.com/opensearch-project/OpenSearch/pull/1500) implementing support for it.

See also the [corresponding issue](https://github.com/opensearch-project/OpenSearch/issues/1286) 

I believe it would be great for end users if you could take inspiration from the PR and work on this feature.

Great blog about the Lucene feature:
https://blog.mikemccandless.com/2019/10/concurrent-query-execution-in-apache.html?m=1
See also those performance results:
https://engineeringblog.yelp.com/2021/09/nrtsearch-yelps-fast-scalable-and-cost-effective-search-engine.html
test/framework/src/main/java/org/elasticsearch/test/ESIntegTestCase.java
*/
        int numDataNodes() default -1;
        /**
         * Returns the minimum number of data nodes in the cluster. Default is {@code -1}.
         * Ignored when {@link ClusterScope#numDataNodes()} is set.
         */
        int minNumDataNodes() default -1;
        /**
         * Returns the maximum number of data nodes in the cluster.  Default is {@code -1}.
         * Ignored when {@link ClusterScope#numDataNodes()} is set.
         */
        int maxNumDataNodes() default -1;
        /**
         * Indicates whether the cluster can have dedicated master nodes. If {@code false} means data nodes will serve as master nodes
         * and there will be no dedicated master (and data) nodes. Default is {@code false} which means
         * dedicated master nodes will be randomly used.
         */
        boolean supportsDedicatedMasters() default true;
        /**
         * Indicates whether the cluster automatically manages cluster bootstrapping and the removal of any master-eligible nodes. If
         * set to {@code false} then the tests must manage these processes explicitly.
         */
        boolean autoManageMasterNodes() default true;
        /**
         * Returns the number of client nodes in the cluster. Default is {@link InternalTestCluster#DEFAULT_NUM_CLIENT_NODES}, a
         * negative value means that the number of client nodes will be randomized.
         */
        int numClientNodes() default InternalTestCluster.DEFAULT_NUM_CLIENT_NODES;
    }
    private class LatchedActionListener<Response> implements ActionListener<Response> {