the question remains if other platforms and services do not use this and stick to google authenticator and authy, what choice do we have as end users?
As far as I know, the platform/service doesn't even know what 2 factor authenticator app you're using. So this shouldn't really be a problem to be honest. You could probably even use a 2FA app you develop yourself(if you know how to, of course).
(correct me If I'm wrong, though I'm very sure of this.)
No. Well as far as I know I mean.
I know some platforms want you to use Google authenticator only. Or Authy only. Or whatever app it its that they are supporting. I would like for someone to confirm or deny this please.
Because otherwise this could change the way I use 2fa because obviously I have been doing it wrong.