I recently had the same realization and moved all my functions to a simple stand-alone server. Besides the normal AWS costs, what scares me most about AWS is the possibility that someone could try to DOS me, leaving me with a huge AWS bill, because there is no real way to limit AWS spending.

The main reason why I keep coming back to cloud providers is databases. I don't feel comfortable setting up a high-availability db setup, and I don't want the responsibility of managing backups. But if you go to, say, Hetzner, you won't be able to use a cloud database in the same network.