It is worth noting though, that Proton doesn’t allow you to use certain domains for recovery addresses. Admittedly this was awhile ago and maybe things have changed there but when I first joined Proton they wouldn’t allow me to set a duck.com or simplelogin.com or addy.io address as a recovery email.
Obviously using an apple ID is stupid but Proton could make more of an effort too.
Being old does the trick for me.