1. fly.io sells redis hosted by upstash. But you are correct in the sense that default fly.io PostgreSQL was unmanaged and probably subsidized, and recent PostgreSQL is probably more expensive. But while I think you cannot directly say that tenfold increase in price means tenfold increase in complexity, I am just saying that it is complex.

2. It is surprisingly common to see people preferring Lucene-based search engines over Postgres. I don't know about your alternatives and not saying anything about them.