Heya, I called the Apple Store, told the bot what I needed to do, eventually just said talk to a human, and then the human took my card details (except for the security code) to add a new card as the payment method.
I think if you want to retain the existing card you'd need to speak to the bank.
The person on the phone can access your order and see all the failed payment attempts.
So frustrating that their 2FA system is just broken. I tried 3 cards at 2 different banks and on 2 different browsers, so it's not our fault!