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
@Inherited
    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.TYPE)
    @TestGroup(enabled = false, sysProperty = ESIntegTestCase.SYSPROP_THIRDPARTY)
    public @interface ThirdParty {
    }
    
    public static final String SUITE_CLUSTER_NODE_PREFIX = "node_s";
    public static final String TEST_CLUSTER_NODE_PREFIX = "node_t";
    /**
     * Key used to eventually switch to using an external cluster and provide its transport addresses
     */
    public static final String TESTS_CLUSTER = "tests.cluster";
    /**
     * Key used to eventually switch to using an external cluster and provide the cluster name
     */
    public static final String TESTS_CLUSTER_NAME = "tests.clustername";
    /**
     * Key used to retrieve the index random seed from the index settings on a running node.
     * The value of this seed can be used to initialize a random context for a specific index.
     * It's set once per test via a generic index template.
     */
    public static final Setting<Long> INDEX_TEST_SEED_SETTING = Setting.longSetting(
        "index.tests.seed",
        0,
        Long.MIN_VALUE,
        Property.IndexScope
    );
    /**
     * A boolean value to enable or disable mock modules. This is useful to test the