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
} catch (IOException e) {
                throw new SearchException(shardTarget, "failed to create sort elements", e);
            }
        }
        context.trackScores(source.trackScores());
        if (source.trackTotalHitsUpTo() != null
            && source.trackTotalHitsUpTo() != SearchContext.TRACK_TOTAL_HITS_ACCURATE
            && context.scrollContext() != null) {
            throw new SearchException(shardTarget, "disabling [track_total_hits] is not allowed in a scroll context");
        }
        if (source.trackTotalHitsUpTo() != null) {
            context.trackTotalHitsUpTo(source.trackTotalHitsUpTo());
        }
        if (source.minScore() != null) {
            context.minimumScore(source.minScore());
        }
        if (source.profile()) {
            context.setProfilers(new Profilers(context.searcher()));
        }
        if (source.timeout() != null) {
            context.timeout(source.timeout());
        }
        context.terminateAfter(source.terminateAfter());
        if (source.aggregations() != null && includeAggregations) {
            AggregationContext aggContext = new ProductionAggregationContext(
                indicesService.getAnalysis(),
                context.getSearchExecutionContext(),
                bigArrays,
                clusterService.getClusterSettings(),
                source.aggregations().bytesToPreallocate(),