Unable to switch Xbox accounts or sign in with a different account on the Microsoft Store

I am trying to re-install Microsoft Flight Simulator 2020 on my PC but it is on another family member's account which usually isn't a problem, but on Windows 11, the Sign-in button doesn't work in the Microsoft Store (it literally does nothing when I click it) and if I start on the webpage (signed in with the right account) and click to open the link for MSFS in the Windows Store app, it lets me click "reinstall" but directs me to the Xbox app which has the same problem with the Switch Account button.

Is anyone else having this problem? Any tips are appreciated.

Thanks!

Could you first sign out from Xbox service, from MS Store and switch the Windows 11 account from MS to local? After that you should be able to use another account in Store and Xbox (the same way like you can use another account for these services in web browser). Alternatively, you can create another user account in Windows 11 for the second family member.