Why does AppleCare+ pull from a different acct from my Family Sharing plan and how can I fix it?

I bought my iPhone in ‘21 and set up AppleCare+ at the Apple Store at time of purchase, using my Apple ID and a bank debit card. Then, my dad enrolled me into a Family Sharing plan. The AppleCare+ continued pulling from my debit card for the next two years. Now, I am switching banks and find that I am unable to change my payment method this at all without disenrolling from the Family plan. Apple’s official guidance is ‘change your Payment Method’ but I can’t seem to even force it to ‘forget’ my old debit card so it would switch over to the Family Sharing card.

I seem to only have three options:

1. cancel the card now that I’ve moved banks, and lose my AppleCare+ when the charge declines.

2. Move $8 into an old bank account every month just to pay this one bill

3. Let it draw down my bank account until I’m overdrawn

Apple, please tell me there is a better way.