It looks very ugly. I dont understand why they wouldn't at least give you the option to revert back.

Both my macbook and my apple TV are up to date. I do not have an antivirus installed. Airplay works but screen mirroring does not. Screen mirroring does work on my iphone. When I downgraded my macbook to catalina, the screen mirroring problem resolves. However this is not a good solution to the problem.