''This Apple ID has not yet been used with the App Store'' loop - Macbook Air M1

When I try to sign in to an Apple Store (the first time) on my new Macbook Air M1 (up to date, macOS Big Sur Version 11.5.1), I get this pop-up, and then when I try to review my information so I can continue with the process normally, the only thing I get is sign-in window again which just continues in a loop.

I already updated all my credit card/billing/shipping info on the Apple ID page and I have no way to enter Media and Purchases (some solutions on the internet were connected to it, as far I can see).

Any help is greatly appreciated, it is really frustrating not being able to buy and download apps from the store.