FWIW my US bank works on GrapheneOS and they refund all ATM fees, so you can use any ATM you want. The only issue I've run into with them is they have a Zelle integration which is only available on the phone, and on GrapheneOS it just loads to a blank white screen. But that seems to be Zelle's fault. The bank is Charles Schwab if anyone is looking for a currently-compatible-with-GrapheneOS bank in the US.

Most credit unions use "shared branching" which mostly solves ATM access.