If you can't get a banking app to work create a secondary user profile, install sandboxed Play Services and install the app there.

If it still doesn't work, enable Exploit Protection Compatibility Mode first via 'App Info', still have issues then finally enable native code debugging for it.

Check this link for a community compiled resource on Banking App Compatibility and contribute if you can:

https://privsec.dev/posts/android/banking-applications-compatibility-with-grapheneos/