This one is definitely the hardest and is the least mature. Have you managed to get off Google on your phone?
I'm using GrapheneOS (Degoogle'd android) on a Pixel 6a. The irony isn't lost on me that I had to buy google to get off google.
I had tried Pinephone and Plasma mobile, but it still needs more work and I needed a phone sooner as my old one was failing.
How about you? Did you manage to get away from Google?
I've been on Graphene for 2 years now, and all my banking apps (from 3 different countries, business and personal) work perfectly. I used Calyx for a while, and everything worked there as well. For most deGoogled OSs that allow to te-lock the bootloader, there should be no issues when using banking apps.