What a strange response. You've said that deferring updates can't be done on Windows. It's plain factually incorrect. You're literally quoting that policy can control it but saying it can't be controlled, but you see no contradiction. Real enterprise uses WSUS, which absolutely can defer updates, it's one of the main selling points.

Not everyone uses that, and group policy is sufficient for plenty of orgs. The link in my earlier comment clearly explains how policy and registry settings can avoid OP's problem, so "no you can't" alone, is a ridiculous and incorrect response. That there exist cases where enterprise makes it more difficult does not mean that it is not possible. It's arguably easier with enterprise because IT can push those settings out to everyone and make sure no one has those interruptions.

Hence the qualifier:

At least in theory

Your IT dept. has to be pretty shit if they're controlling those policies but not setting basic work hours. Turning off that restart asap crap is the norm, because management/c-suite get pissed off by random restarts and immediately blame IT.