Switch Apple subscription payment method

I'd like to switch the payment method of my iCloud+ and Apple Music subscription to Apple Pay. It is currently PayPal. I was under the impression that adding Apple Pay to the top of my list with payment methods would make it switch automatically the next billing. But that doesn't seem to be the case. I also cannot remove the PayPal method: "Unable to Remove. There is an active subscription on this account that requires at least one payment on file." Do I have to cancel the subscriptions first?