Can’t subscribe to Apple Arcade

Hello,

I‘m trying to subscribe my mothers account to Apple Arcade, but I can‘t find the option. It opens the App Store but there is no option to subscribe. When trying to download any game it says I must be subscribed but no option to do so.

Also, her account is part of the family group. Her and my account are registered in different countries. I got the Apple One Family subscription but sharing the subscriptions won‘t work because of that. Could it be that she can‘t subscribe because of it shows up that she is already „subscribed“? If so, how can she subscribe to Apple Arcade without having to leave the family group?

Thank you