Cool! Seems very productive. Only thing I'm thinking of is reliability and the lack of control since you aren't hosting it yourself.
Reliability, it depends on your app and requirements. Been using them for about a year and it has been really solid, the few times I did have some issues the support was really quick and helpful. But I do see your point, it might not work for everyone.
I still find it important that the option exists if ever needed, and maybe even more important is the ability to move away from Supabase, which some people have done successfully (see for example https://news.ycombinator.com/item?id=36004925)
Other services like Firebase make that really complicated. I quite like that portability is one of their core principles.
There are some guides and templates on self hosting https://supabase.com/docs/guides/self-hosting but it's obviously a big complicated project with lots of features. It probably also requires a bunch of work to monitor, maintain and update it once you get it running.