2FA is not an issue. Many, but not all banking apps work fine. I have an android phone for 3 apps which I need about once a month. Daily driving a linux phone since 2016.
I never really did a lot of banking on my phone before, but it really wasn't that hard to let that go. I'd say the biggest hangup is not having Venmo or something for splitting bills with friends, yard-sales, etc, but I've started carrying some amount of cash again for those instances and it's worked out alright.
Been daily driving a dumbphone since 2023. Yes it takes a bit of work, but it's so SO worth it.