How does this work when I need to log in to a new computer and my phone has no internet? As far as I can tell, that would render all of the given methods usele

How does this work when I need to log in to a new computer and my phone has no internet? As far as I can tell, that would render all of the given methods useless. You're going to need more specifics if you want to convince people that this is both secure and convenient - otherwise we're going to stick with TOTP.