You're right that vanilla Postgres doesn't come close to replacing Elastic. There are efforts to resolve this, though, like ParadeDB: https://github.com/paradedb/paradedb (disclaimer: I work for ParadeDB)
"Disclaimer" means "don't take this seriously because I'm not an expert". You mean "disclosure".
I see Tantivy mentioned in your readme but AFAICT there is no PG-Tantivy sync. I also see "native vector support is coming to our search index soon". Could you clarify?
What do you suggest for a language like Malayalam which has no native support, preferably with low RAM requirements?