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
No! I believe it is forever, as it is linked to a company, hence the MDM message. I'm the same, I managed to solve it, it's great, using Sonoma 14.0, without pop, but I'm not free from Apple's ping.