In my case some of my banks will work without the google play services but I have one that requires it. It hasn’t been a problem for me so far. The grapheneOS community forum has some good info on which apps are problematic and workarounds. I’m aware of a couple of banks that don’t work on GOS due to the OS Attestation.

I switched to GrapheneOS with zero regrets. Mainly because Google is deeply embeded in the Android ecosystem. There was no way i was going to add Samsung AI crap on top of that mess.