what do i do whenever it says this payment method already is added.

Re: "what do i do whenever it says this payment method already is added but continues to say i need to update it?"

Maybe check to see if the card has expired, and update the expiry date if needed:

How to change an Apple ID payment method:

If you need to change or update your Apple ID payment method – Apple Support

If you need to delete an old card, you would likely need to add a new card first, in order to keep the account active (ie: for subscriptions etc.)

How to add an Apple ID payment method:

Add a payment method to your Apple ID - Apple Support

How to delete an Apple ID payment method:

Remove a payment method from your Apple ID - Apple Support

If still needing help:

Try updating to the latest iOs 16.4.1 if you haven't already done so,

else

Try restarting your iPhone: Restart your iPhone - Apple Support

(Will often restore order, I something is not working right,)