[Arch-TK]

Device attestation works for banking applications on GrapheneOS.

The only thing which doesn't work is google wallet because they explcitly expect a Google signed operating system.

[drowsspa]

That's probably what those apps use, then. Because all those tricks people mentioned never worked. Some explicitly failed saying that my ROM signature wasn't official.

[Arch-TK]

Have you actually tried using your banking application on a recent (post introduction of sandboxed Google Play) GrapheneOS?

Restricting things to only Google ROMs basically also means your banking app won't work on a bunch of non-google Android phones and even most banks don't want to go that far.