Woudl it not just be easier to block the IP addresses?Restrict Software Update with a configuration profile
AutomaticallyInstallMacOSUpdates
AutomaticDownload
AutomaticCheckEnabled
all set to false, payload scope System
https://developer.apple.com/documentation/devicemanagement/softwareupdate
Apple Configurator https://apps.apple.com/app/id1037126344
iMazing Profile Editor https://apps.apple.com/app/id1487860882
ProfileCreator https://github.com/ProfileCreator/ProfileCreator