I cannot edit my payment method

Any restrictions set up in the settings for Screen Time?

Did you follow the steps in this article to change the payment info?

Change, add, or remove Apple ID payment methods - Apple Support

Just found it, you have to do it through iTunes Account. The option is greyed out on the website. If you don't have the app on your computer, download iTunes it and follow the payment options to change your address there. Absolutely unreal that you have to do it that way.