Earlier quoted context omitted.
Which banks? Which country? How do they check and enforce iPhone / Google wrt. 2FA? Are you referring to TOTP as 2FA?
All banks are required to have "safe" 2FA in the EU by EU regulation. SMS is banned. Most banks in Germany, Austria and Portugal default to Play Store or App Store apps with OS integrity checks. It seems like the Nordic countries have it a bit better with the ID reader apps. There are sometimes alternatives and some of them require paid subscription. The apps they require are proprietary. They are not generic TOTP ge…
Hungary is in EU and the most popular bank sends a one-time code (with expiry) via SMS for logging in, making a transaction, for the mere displaying of "Telecode", and so on.
There is no TOTP, only this one-time code sent via SMS.
I do not use their apps on any platform. I login via their website when I need to which is rare. When I make a payment via card, I have to provide the provided 3-digit "Telecode" and the one-time code sent via SMS. There is an option "What if I do not have access to that phone number?" or whatever the literal translation is, but I have not checked that out yet.
... which is why I left a comment asking you about the details. You telling me SMS is banned and referring to EU regulations just left me more confused given the above.