csrutil disable
Restart computer
In the terminal, type
sudo open /Applications/TextEdit.app /System/Library/LaunchDaemons/com.apple.ManagedClient.enroll.plist
change
<key>com.apple.ManagedClient.enroll</key>
<true/>
to
<key>com.apple.ManagedClient.enroll</key>
<false/>
So that the changes take effect
There are multiple past posters that have used the same methods with success. There may be a typo or error or special case with your system. If you would like, I can take a look using a tool like AnyDesk after day business hours.