Xbox Windows 10 app looping indefinitely at sign in

That's what I like to do seasonally when I see my computer is a mess. Save only some important files and format everything

that's odd. Try doing an in place upgrade, this link has detailed instructions on how to do this.

https://answers.microsoft.com/en-us/windows/for...

I did the in place upgrade, installed every single update, and yet nothing - the problem still persists.

Followed your instructions step by step but unfortunately it didn't work

I'm Samy an independent advisor and I'll be helping you

Close the Xbox app and open the Xbox Companion app, if you don't have this app installed, download the app using the Microsoft Store on your Windows.

Then open the app, log in with your account, open the Xbox app and see if that resolves the issue.

Honestly, I'm out of ideas of what to suggest, mate