I mentioned this yesterday on the Google only allowing verified developers story, but my banking app works fine on GrapheneOS, as do many others. There is a crowd sourced list of their status here: https://privsec.dev/posts/android/banking-applications-compa...

Depending on what your bank's app actually does, that might not be a big problem.

If it is, there's a good chance LineageOS with root and Play Integrity Fix will work, at least it's been working for me for years.

It does not matter whether it works. It is a contract violation and, for some banks, a reason to debank you if found - check the bank app's usage terms and conditions.

Then get another bank. Or better yet, don't bank on a phone.