For mail, the answer is to own your domain. If you move away from (probably) Gmail, you don't want to lock yourself into an @proton.me. Get your domain, and use whatever provider you want (it can be Proton, but there are many others).
Even for own domain, what are the risks of choosing a .com domain and US based registrar if your country can potentially be hit by sanctions or your registrar tends to develop a sudden surge of misplaced morality.
