The tldr is that using LiteFS with worker instances is not a good setup. LiteFS works well when you can fly-replay HTTP requests that do writes, it’s less useful for running a bunch of processes that need to write to sqlite.
If you want to run workers that also use LiteFS, you’ll need to come up with some mechanism for sending writes to the primary instance. I probably wouldn’t bother doing this, though, it’s not the sweet spot.
This is just a limitation of LiteFS and using sqlite directly. For what you’re doing, I expect you’ll have much more success with https://turso.tech/