Elasticsearch in later versions has done quite a lot in terms of memory reduction. Last section of https://www.elastic.co/blog/three-ways-improved-elasticsearch

Elasticsearch in later versions has done quite a lot in terms of memory reduction. Last section of https://www.elastic.co/blog/three-ways-improved-elasticsearch-scalability https://www.elastic.co/blog/three-ways-improved-elasticsearc... but it has been an ongoing effort in multiple of the later 7.x and and 8.x releases.