HN does not allow you to delete comments. I would ask that if you think that not having Yubikeys does not require a significant and immediate answer from the ProtonMail team, to sign your name (I will) at the bottom of your response. If you can’t do that, perhaps provide a burner email address.
Dan Ehrlich
dan@ehrlichserver.com
CISSP, CCSP, CISM
EDIT: spacing between my signature, change of comment to commentS