Reading up on Loki, it seems it lacks full-text search, prefering something called 'distributed grep'.

I'm also looking at sonic, which is a new full-text search engine in rust with less overhead than Elasticsearch. It's lacking a gui focused on log search.

Could they work together somehow, maybe as an alternative backend to you distributed grep?

Sonic does not store the original content, so it could store a reference into your compressed chunk.