e.g. in Germany you have similar situations when it comes to online banking for some banks (through not when it's about card->terminal payment)
for example credit card apps in the EU have 2FA (which doesn't always trigger and there is still the legacy protocols for payments from outside of the EU so a bit uh, maybe, pointless)
this 2FA is for most banks handled by and app (different apps tho)
and many of this apps bathed in "security" snake oil making them impossible to run even on a non-rooted but de-googled android phone
same for pay with you phone over NFC, e.g. it currently doesn't work for my bank with my phone and I'm speculating that it's because the secure modules attestation is not is not whitelisted (the phone uses a "industry" ARM chip instead of a typical consumer one so attestation derived ids/keys can be "unexpected")
(Through also where I live there is a law for having some kind of b2b online banking API, so theoretically a company could create an app which does work on unusual phones, or create a device like you mentioned.)
To boil down the problem: To access the western systems you need to keep feeding Apple, Google and Microsoft (AGM).
The alternatives are non-existing still 15 years after the release of the smartphone (that in retrospective probably was the dumbest thing humans have made).
The dream device = dual boot tablet Android/iOS and vanilla linux will never exist?
So you have to shoot for vanilla linux (maybe ARM, probably RiscV) and tell the banks that you are dropping support for AGM.
It's a "I'm not in here with you, you are in here with me" sort of moment.
This goes hand-in-hand with root certificates, taxes and the health/legal system at large; everything made by humans without consulting nature first.
I got popcorn, but I'm kinda worried too.
BankID is owned by the Swedish banks. It is required for some government- and healthcare sites as well, despite it being a commercial monopoly.