I'm not using Google play or any other services on android over 6 years now. You don't need banking apps for making transactions.
You can get a little hardware thing to generate their OTP codes, as an alternative to apps.
The website shows you a code. You input it into the reader, followed by your card PIN. The reader outputs a code you put into the website.
This is what it looks like:
https://www.post.ch/-/media/portal-opp/k/bilder/postgeschich...
for anything EU or eu commission, you must either have an app in stock OS smartphone, or receive a sms on a network they can validate sim is attached to a tax id, or nothing else is allowed. totp et al is legally verboten.