I completely understand you, but the thing that changed everything for me is that Supabase is Open sourced and based on just Postgres. You can run it yourself from day one on your infra if the hosting provider/geo is essential for you.

And if you start with managed, you can easily migrate all your data using just pgdump. All other services you can run yourself and update source codes accordingly to your new requirements. Or completely replace one by one if necessary.