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
}
    private static boolean runTestScopeLifecycle() {
        return INSTANCE == null;
    }
    @Before
    public final void setupTestCluster() throws Exception {
        if (runTestScopeLifecycle()) {
            printTestMessage("setting up");
            beforeInternal();
            printTestMessage("all set up");
        }
    }
    @After
    public final void cleanUpCluster() throws Exception {
        
        
        
        if (isInternalCluster()) {
            internalCluster().setBootstrapMasterNodeIndex(InternalTestCluster.BOOTSTRAP_MASTER_NODE_INDEX_AUTO);
        }
        super.ensureAllSearchContextsReleased();
        if (runTestScopeLifecycle()) {
            printTestMessage("cleaning up after");
            afterInternal(false);
            printTestMessage("cleaned up after");
        }
    }
    @AfterClass
    public static void afterClass() throws Exception {
        try {