After running sudo apt upgrade and subsequently rebooting, my system isn't letting me log in. I'm entering my password, then the screen turns black or unresponsive and after a few seconds it will push me back to the log-in screen.
Logging in via Xorg lets me get a step farther and actually loading the "home screen" and then it displays "Oh no! Something has gone wrong. Please log out and try again"
Welcome to the Forum!
Do You remember what Packages were updated?
Also just to confirm, are you running version 16 of Zorin? If so, it would definitely be time to be thinking about an upgrade to your system, as Zorin 16 is out of date and no longer supported.