Everything can be fixed - it is a question if it can be done with an anywhere near reasonable amount of work. NFC supposedly is mostly just a toggle away - Bluetooth not so much.
However, if you are that deep into being dependent on Android, you should probably consider if Sailfish OS is really for you.
I for one would never buy an app-car - what would you do when the app goes unmaintained or similar? Scrap the car? I’d also never use a bank app (websites work just fine!). Though unfortunately the eID solution here in .se is app-only and owned by the banks, with a similar activation procedure - or you can just show up at a physical office.