Hey there,
Thanks for the update and for giving those steps a shot, I really appreciate you sticking with it.
Since we’ve ruled out the Insider program and family settings, and the usual fixes didn’t work, it’s likely that the issue is deeper in the system’s network or profile sync layer.
Sometimes, the console fails to properly handshake with Xbox Live during startup, which causes the login screen to glitch or loop back to the dashboard without signing you in.
Let’s try one more method that works around that: open the Xbox app on your phone, go to the Devices tab, and try connecting to your console remotely.
Once it’s paired, use the app to sign in to your account, this can sometimes push the login through when the console itself won’t do it.
Also, if you haven’t already, try switching your console to a mobile hotspot or different Wi-Fi network temporarily, just to rule out any network sync issues.
Quick check, when you did the factory reset, did you choose “Reset and remove everything” or “Reset and keep my games & apps”?
That detail helps me know if we need to go deeper or try a different route. Let me know how it goes.