I use Proton's email aliases for throwaway accounts, and I have a catch-all on my own domain and use custom email addresses (think apple.com-randomstring@example.com) for accounts that I intend to keep until I die.
I do something like this with Proton and my own domain as well. However, I made the mistake of buying a .io domain, thinking England would be pretty stable. Now I need to figure out what I’m doing.