Yeah but even for device administrators using bleeding edge “Declarative Device Management” the “your Mac must be on this version by this time” thing is really hit or miss. I was testing it yesterday just telling a test computer to update to 15.7.1 and while I got nagged to hell, it never actually rebooted to start the update. This is despite claims in each of the nag messages that it would.
At least Apple is still somewhat deferential to the user experience.
Is there even a way to automatically upgrade to a major macOS version? Automatic update settings are only for minor/patch and security responses.