> I can use my bank on some linux distro,

Yes, I've been doing that since 2009 on Ubuntu and Debian but there are several caveats.

One of those banks has its own TOTP device and they won't replace it when the battery dies. It's almost 20 years old now. Then it's the fingerprint sensor on my phone.

The other banks authenticate accesses and many operations with either their app + fingerprint (all of them) or SMS (some of them). So basically I would still need a phone with a blessed OS. I could buy the cheapest one and store it in a drawer, but it's still a dependency on Google or Apple.

GrapheneOS requirement of Pixel devices is a dependency on Google too.