I don’t know whether you have the same issue but I got stuck on the EULA page because there’s a birth date selector behind it and they made both modal. The date picker is active but the EULA is on top so you can’t do anything. Tried in both Firefox & Chrome.

The solution for me was to just go back to the store page while signed in, choose a conforming birthdate and then the EULA page worked normally.

Checkout page is just badly written