I have been using the RBC banking app without issues on GrapheneOS.
Except at one point I made three unsuccessful login attempts and was locked out. This wasn't a problem as I got the bank to unlock it by visiting their location, however while I can log in from a browser, I am unable to log in through the app.
I tried removing all data from the app, reinstalling it, but to no avail. Even the bank does not know what the problem is and advised to reinstall the app and ensure the OS is updated (which it is). They believe it has to do with my phone as my account is unlocked from the bank's side.
All I know is that the app needs Google Play Services to work, which I ensured was enabled while trying to log in.
Other than that, the only thing that comes to mind is that originally I had to enable Exploit protection compatibility mode for the app to work, but at some point it changed such that it only works if all GrapheneOS app hardening features are enabled; though I do not know if that has to do with the current situation.
Any ideas?