Would an alternative be to offer auto-generated usernames that you have one-shot to generate a password for and if you lose that password you're gone? Something like opposite-dwindling-zodiac, casino-smile-widget, or creative-crumpled-dismiss?
If you choose to add a phone number as a recovery (and for contact finding) that's your optional choice.
If you choose to add a phone number as a recovery (and for contact finding) that's your optional choice.