Can’t add a payment method from a bank outside my region

I recently moved to Germany, and I’m using my Austrian bank account here since I used to live in Austria and both accounts are in euro. However, Apple won’t accept me adding my Austrian bank (or my US or Uk ones) to my German Apple ID. Whenever I ask for help from support they just tell me to consolidate my three IDs to the German one, but that’s completely not the question, and would also remove the only way I have to pay for my purchases (for some reason, my UK bank is still accepting my old UK address when I file it through my UK Apple ID, even though in fact all of my payment addresses are here in Germany of course now. Whereas Apple also won’t accept a payment address in a different country than the Apple ID, otherwise I’d just make an Austrian one.) Anyway, that doesn’t seem relevant at all, I think they aren’t having humans read my complaints. If I could just get a payment working on my German Apple ID, I’d be OK with shutting down the other two since I no longer am splitting my time between the UK & US, in fact given COVID I don’t even travel to those countries right now!