linc Sonic looks interesting and I hadn't come across it previously, but I have reservations about new, single-person projects like that.
It's also not really an Elasticsearch alternative, it doesn't feature ranking for example which is quite an important feature.
I've personally run tests with Meilisearch and Typesense with over 600k posts indexed. I don't like how Typesense works, it's still definitely a beta and I couldn't get accurate or consistent search results with it. Meilisearch is instead much better in my experience. Also, I'm not seeing the issue mentioned in the first post, search results are always returned in a few milliseconds, usually <15 ms (unless I use Docker volumes on Windows/macOS, but the documentation is clear about that).
I know you didn't ask but I thought this might be helpful to someone ahah 🙂