I used to try 11 when I'm an insider, but feel it's not for me. It seems like an unfinished product, so I reverted to 10. Recently get a banner showing my machine is ready for 11, and believing that problems in early days should have been solved, I gave it a try, only to roll back 30 minutes later.

The default browser thing is a factor that cause me to revert, but I also got a problem relating to "Microsoft.Windows.SecHealthUI". Somehow its residue from 10 got removed, and the start menu just show the icon of an app that is not functional and cannot be removed. I know Windows Defender/Security can be opened manually, but seeing this kind of thing makes me feel that Windows 11 was a joke, and until they seriously tackle the issues, I will simply remain with 10.