There are few Rust based projects now for Full Text Search. So you can move away from JVM.

- https://github.com/valeriansaliou/sonic

- https://github.com/toshi-search/Toshi

Great, I would love to hear your feedback on Typesense then. It's not meant to be a full-blown ES replacement. Elasticsearch is a beast but most people don't need that (atleast to begin with).

You could use Lucene directly in a couple of languages:

Python Port: https://lucene.apache.org/pylucene/index.html

.NET Port: https://lucenenet.apache.org/

Please also check Xapian [1].

[1] https://xapian.org/

FTS in PostgreSQL is pretty good, except for missing rank algorithms like tf-idf.