I just had to tweak the permissions for MobilePay, I cannot remember exactly which, but I think it was something about allowing it to use the Play Store integrity layer? It was a quick fix in any case, and they have some advice on the Graphene site.
For banking Revolut works with no issues. I have not tried my main bank, I never use their app, always do my banking on my laptop anyway.
I also switched to Kvaesisto from Nova. Its quite different, and I had to get used to it, but I really love it now. I don't think I'll ever want to switch.