I setup a fresh rails 8 app on Fly last year, using PG for the main data store but using SQLite for the ancillary solid stack dbs.

Only fuss I remember encountering was with fighting with rails migrating solid queue properly, but this seemed like a rails unit issue and don’t remember it being a Fly issue.

I’ve been contemplating migrating my pg primary to SQLite too. Anyways don’t have much else to offer other than an anecdote that I’m happily using fly with partial SQLite.