Moving away from ProtonMail I looked at several options. Changing email addresses everywhere when I change providers seemed so unflexible, so I've set up a #selfhosted SimpleLogin (npub18kn…x57j) instance and moved all my aliases there.
Right now my default mailbox points to Tuta (npub1tk7…0m5c) but changing email providers is just changing the address of the default mailbox in my SL instance!
And I can even use PGP between SL and the mailbox, if there are add-ins or the provider supports it ootb.