No login possible on Xbox app on Win10

Just now I've tried the Xbox app for the first time and it's a dreadful and quite pathetic experience from a multi-billion dollar company.

First off I had to troubleshoot for like 1h because the login window in the app didn't even appear, as it just flashed repeatedly for a few times, and as it turns out there was this Xbox auth process which is needed, but wasn't running at all, which already points to "spectacular" software design in being reliant on certain processes without checking them or telling the end-user of their importance.

After I did that I could finally see the login window, but now logging in does absolutely nothing: I press the button and nothing happens, not even an error message or something.

So off to another troubleshooting tour, already massively annoyed, and after skimming through countless threads it seems that the Xbox app relies on account details saved in the Window profile, but I can't access them because for some reason my Windows profile is a mess as I can't even access the list of accounts under Settings -> Accounts -> Emails & accounts.

Am I right in that assumption?

In every other storefront app like e.g. GoG Galaxy, Steam or even the EA launcher I can login using the conventional method of typing in account-name and password, but only in the case of the Xbox app have I ever experienced something this bloated and confusing by not getting a login screen and instead some other login credentials being used automatically without being asked first + those credentials not even working.

Guess I take the 1€ loss for the first month of pc game pass and cancel immediately.

:)