Payment Method Disappears When Upgrading Storage

When I try to upgrade my iCloud storage plan, my default payment suddenly disappears from payment methods. Step by step:

1) I go to upgrade plan, double click side button to buy, and it says my payment method declined.

2) I hit continue to update/add payment. Even though I have added my debit card (which is from an accepted major bank in my region) to my wallet and verified it, it does not show in my methods of payment specifically on this screen. It only shows my $0 Apple Cash balance.

3) If I attempt to add via debit/credit the same debit card that is already in my wallet on any other screen and set to my default payment (though for some reason not showing up here), it gives me an error saying this card has already been added to your wallet. Again, though, on this screen it does not show as a payment option.

4) I go back to my payment methods in my appleID and there is an error listed under my debit card now saying I need to verify or update my payment method to avoid disruption of subscriptions, etc.

5) I will click “Done”, it “updates”, and the error is gone.

6) I then proceed to try to upgrade plan again, and the same steps 1-5 repeat. My card doesn’t show up as a payment method, it cannot be added because “it’s already been added”, and when I go back to appleID payment methods, the error is back again listed below my card.

I’ve turned my phone on and off again, opened and closed all of these apps, removed the debit card and added it again entirely. It keeps happening. The card is not expired, all my subscriptions for my current iCloud Storage plan, Apple Music, and AppleCare all successfully were charged to this debit via my wallet/default payment being set this past month, so it still works.

What’s going on?