You are not going to like the answer, but... I just don't do banking on a phone. I never did. Never trusted something that important on a device I'm carry around all the time. I do it on the desktop, which has an operating system I trust (Linux), that can't get on anyone else's hand.

I'm sorry. I wish I could give a solution. This has never been a problem to me but I understand it's a massive thing for a lot of people.

On a more complicated option, the answer is: it depends. If you have a pixel with grapheneOS and you relocked the phone, I think a lot of bank apps will work. Or maybe a different bank doesn't require that, or allows you to do it on the browser. I usually ask the bank before signing in if they will require me to use an app. If they do, I don't chose them.

The reasons to require the user to use the app are almost always evil, anti-user, and shows it's an organization that will fuck you up down the line, so it's a good filter for me. A red flag.

But yeah, sorry. I'm just the wrong person to ask. Maybe someone else who looked into the subject can suggest something. I never even bothered finding a solution because I never saw a problem.