I've had no trouble with banks, brokers or payment networks on GrapheneOS but I don't use crap like company-X pay wallets..
I admire this effort. However I don't care that much about my privacy and I don't care about extended security. All I want is a basic Android system without any of added apps, without any AI. I want the most basic apps for phone, SMS, camera. And I want working Google Play to install some additional apps. I want OS focused around this goal. Not OS focused around extended security or privacy.
So it's like suggesting to buy M1 Abrams instead of Toyota Land Cruiser.
I'm embracing ascetic computing. I'm using Arch Linux with bare minimum of apps for my desktop. And I wanted to do the same for my smartphone. Pixel is incredibly bloated. I spent few days just navigating its maze of settings, trying to disable them all. At this point, I'm back to my old iPhone, which at least allows me to uninstall almost every single app and old enough, so it does not support Apple Intelligence (thank, god).