In addition to what has already been mentioned: Before you give up or switch banks, be sure to test these workarounds:
https://discuss.grapheneos.org/d/8330-app-compatibility-with-grapheneos
The Play Integrity notificaction “App XY uses Play Integrity API” popping up is a (i guess) GrapheneOS feature to show that an app uses it, but it doesn't necessarily mean that the app enforces it:
There's a new Play Integrity API notification which tells you when apps use it. Apps can use it without using the result to ban using a non-stock OS so it doesn't imply anything is going to be broken when the notification is shown.
source: https://discuss.grapheneos.org/d/19436-grapheneos-version-2025012600-released/4