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
server/src/main/java/org/elasticsearch/search/SearchService.java
* None is intended for use in testing, when we might not progress all the way to generating results
         */
        NONE {
            @Override
            void addResultsObject(SearchContext context) {
                
            }
        };
        abstract void addResultsObject(SearchContext context);
    }
    class Reaper implements Runnable {
        @Override
        public void run() {
            assert Transports.assertNotTransportThread("closing contexts may do IO, e.g. deleting dangling files")
                && ThreadPool.assertNotScheduleThread("closing contexts may do IO, e.g. deleting dangling files");
            for (ReaderContext context : activeReaders.values()) {
                if (context.isExpired()) {
                    logger.debug("freeing search context [{}]", context.id());
                    freeReaderContext(context.id());
                }
            }
        }
    }
    public AliasFilter buildAliasFilter(ClusterState state, String index, Set<String> resolvedExpressions) {
        return indicesService.buildAliasFilter(state, index, resolvedExpressions);
    }
    public void canMatch(ShardSearchRequest request, ActionListener<CanMatchShardResponse> listener) {
        try {
            listener.onResponse(canMatch(request));
        } catch (IOException e) {