Supabase has some good examples on their website, search for hybrid search. I needed to tune the function they have there but it should show you how to approach it.

Here is our doc with RRF:

https://supabase.com/docs/guides/ai/hybrid-search

I'm actually doing something like that already, I'm mostly referring to the Reciprocal Rank Fusion (RRF) part of this to squeeze more out.