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
} else {
                    minMax = null;
                }
                return new CanMatchShardResponse(canMatch || hasRefreshPending, minMax);
            }
        } finally {
            Releasables.close(releasable);
        }
    }
    /**
     * This method tries to rewrite a query without using a {@link SearchExecutionContext}. It takes advantage of the fact that
     * we can skip some shards in the query phase because we have enough information in the index mapping to decide the 'can match'
     * outcome. One such example is a term based query against a constant keyword field. This queries can rewrite themselves to a
     * {@link MatchNoneQueryBuilder}. This allows us to avoid extra work for example making the shard search active and waiting for
     * refreshes.
     */
    private static boolean canMatchAfterRewrite(final ShardSearchRequest request, final IndexService indexService) throws IOException {
        final QueryRewriteContext queryRewriteContext = indexService.newQueryRewriteContext(
            request::nowInMillis,
            request.getRuntimeMappings(),
            request.getClusterAlias()
        );
        return queryStillMatchesAfterRewrite(request, queryRewriteContext);
    }
    @SuppressWarnings("unchecked")
    public static boolean queryStillMatchesAfterRewrite(ShardSearchRequest request, QueryRewriteContext context) throws IOException {
        Rewriteable.rewrite(request.getRewriteable(), context, false);
        boolean canMatch = request.getAliasFilter().getQueryBuilder() instanceof MatchNoneQueryBuilder == false;
        if (canRewriteToMatchNone(request.source())) {
            canMatch &= request.source()