What banking business? Use a web browser, or just bank in person like everyone did not long ago. Carry a credit card instead of Apple/Google Pay. That's what degoogled Android users do and it's a very minor inconvenience anyone with a little bit of maturity should be able to accept. Also, cash is much better for your privacy.
It’s not possible. Logging in to a banking website is becoming strictly speaking impossible w/o a phone.
The country I live in (VN) recently banned online banking without using a mobile app and biometric verification via selfie. The sites had to withdraw access.
Or instead of hamstringing your entire way of life and making things immeasurably harder.. we could regulate them too.
And if you require a one-time SMS code for purchase (which can be adjusted via their website, most likely), then you still have an option that is not Apple and Google. I use a dumbphone for "banking" (SMS)... and a credit card, and the website. Those are really all the 3 things I need to do banking, as you have said so correctly.