I wish I had seen this last night. I first noticed problems when my keyboard and touchpad suddenly didn't work after an update, then got the "app control for business" thing after trying to restore the PC and uninstall a McAfee program that apparently came preinstalled with the Laptop, which had Windows 10 on it when I bought it several years ago. I managed to find another post here related to this about how to delete the policy using citool, but of course got an error indicating I didn't have permission to do that when I tried it. I also ran into a similar issue when using command prompt from the recovery options to mount the EFI partition and delete the contents of the EFI folder, which was another suggested fix. Finally ended up booting into Linux since I have a dual-boot setup, then used a partition manager program to reformat the EFI partition and finally reinstalled Windows from a USB drive.
Definitely not going to go with the Canary channel anymore. Sticking to the standard public release for now until I get everything reinstalled and working properly.