First of all, you are not alone with this issue. This is a very long thread to read with multiple suggestions. I have found none of them that work. Once Windows 11 has downloaded on your computer, the only way to stop the pending installation is to keep pausing it. You can pause it up to 35 days. Right before that, you have do go ahead and click on 'check for updates'. Then what happens it is tells you to pick a time for the installation. You can then pause it again for another 35 days.
I have Windows 10 home version so I don't have that group policy setting like the Pro version does. There is one setting to double check though. In settings, make sure you click the box that says that you have to be notified before installing an update. That way, Windows 11 won't install unless you let it.
No easy answers then you must either let Windows 11 install and hope for the best or keep pausing the rest of your life. Mine is now paused until Feb. 2nd. I'll pause it one more time after that and then I'm going to just let it install.