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
@sonomaccess
Well thats why, this forum is specifically for the #1 I mentioned which is regarding just the notification popups and not removing a mdm profile from your device. Im completely aware that you cannot downgrade OS's unfortunately:/
From my experience I was informed a few yrs ago that upgrading from Monterey to Ventura they fixed it to where you can no longer fresh install a new/same os from a usb drive or ote without connecting to the internet for authentication. On Monterey when I did it you just installed the os ote and upon bootup after the installation you disconnected your router which wouldnt let it authenticate on apple servers. I thought they fixed this in Ventura but there seems to be people here who were able to do it still on Ventura.
Im sure its possible but without a device that has a t2 chip on it Im not really sure I can personally test it out but here are two resources that I suggest:
This helped me ages ago remove the mdm profile from my computer: https://support.addigy.com/hc/en-us/articles/4405907255827-Removing-non-removable-MDMs-by-disabling-SIP
More importantly take a look at the last comment by @nerykell here: https://gist.github.com/henrik242/65d26a7deca30bdb9828e183809690bd