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
this.defaultSearchTimeout = defaultSearchTimeout;
    }
    private void setDefaultAllowPartialSearchResults(boolean defaultAllowPartialSearchResults) {
        this.defaultAllowPartialSearchResults = defaultAllowPartialSearchResults;
    }
    public boolean defaultAllowPartialSearchResults() {
        return defaultAllowPartialSearchResults;
    }
    private void setMaxOpenScrollContext(int maxOpenScrollContext) {
        this.maxOpenScrollContext = maxOpenScrollContext;
    }
    private void setLowLevelCancellation(Boolean lowLevelCancellation) {
        this.lowLevelCancellation = lowLevelCancellation;
    }
    private void setEnableRewriteAggsToFilterByFilter(boolean enableRewriteAggsToFilterByFilter) {
        this.enableRewriteAggsToFilterByFilter = enableRewriteAggsToFilterByFilter;
    }
    @Override
    public void afterIndexRemoved(Index index, IndexSettings indexSettings, IndexRemovalReason reason) {
        
        
        
        
        
        if (reason == IndexRemovalReason.DELETED || reason == IndexRemovalReason.CLOSED || reason == IndexRemovalReason.REOPENED) {
            freeAllContextForIndex(index);
        }
    }
    @Override
    public void beforeIndexShardCreated(ShardRouting routing, Settings indexSettings) {