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
listener.onFailure(e);
        }
    }
    public void canMatch(CanMatchNodeRequest request, ActionListener<CanMatchNodeResponse> listener) {
        final List<ShardSearchRequest> shardSearchRequests = request.createShardSearchRequests();
        final List<CanMatchNodeResponse.ResponseOrFailure> responses = new ArrayList<>(shardSearchRequests.size());
        for (ShardSearchRequest shardSearchRequest : shardSearchRequests) {
            CanMatchShardResponse canMatchShardResponse;
            try {
                canMatchShardResponse = canMatch(shardSearchRequest);
                responses.add(new CanMatchNodeResponse.ResponseOrFailure(canMatchShardResponse));
            } catch (Exception e) {
                responses.add(new CanMatchNodeResponse.ResponseOrFailure(e));
            }
        }
        listener.onResponse(new CanMatchNodeResponse(responses));
    }
    /**
     * This method uses a lightweight searcher without wrapping (i.e., not open a full reader on frozen indices) to rewrite the query
     * to check if the query can match any documents. This method can have false positives while if it returns {@code false} the query
     * won't match any documents on the current shard.
     */
    public CanMatchShardResponse canMatch(ShardSearchRequest request) throws IOException {
        return canMatch(request, true);
    }
    private CanMatchShardResponse canMatch(ShardSearchRequest request, boolean checkRefreshPending) throws IOException {
        assert request.searchType() == SearchType.QUERY_THEN_FETCH : "unexpected search type: " + request.searchType();
        Releasable releasable = null;
        try {
            IndexService indexService;