When I sign into a Google apps account I have associated with a school about half the time I am forced to go through option (3) whereby I’m asked for a number they can send a SMS to. I am never presented with option 1 or 2. Per the tenant settings which I do not control, 2FA is disabled and users cannot enable it, nor provide a backup email last I checked. Extremely frustrating- especially not being able to use a VoIP number, landline to dial, or set up a more robust TOTP generator or the like. Perhaps the school should codify the requirement for students have cellular service just to enroll, since it’s the de facto case already. sigh