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
*/
    public int getOpenScrollContexts() {
        return openScrollContexts.get();
    }
    public ResponseCollectorService getResponseCollectorService() {
        return this.responseCollectorService;
    }
    /**
     * Used to indicate which result object should be instantiated when creating a search context
     */
    protected enum ResultsType {
        DFS {
            @Override
            void addResultsObject(SearchContext context) {
                context.addDfsResult();
            }
        },
        QUERY {
            @Override
            void addResultsObject(SearchContext context) {
                context.addQueryResult();
            }
        },
        FETCH {
            @Override
            void addResultsObject(SearchContext context) {
                context.addFetchResult();
            }
        },
        /**