My laptop (Win10 home) installed updates over metered connections (and actively combated my efforts to disable the update service, take ownership of the service, etc.). Ultimately the fix was to install Ubuntu.
Group policy editor allows you to select what type of updates you want (if any), if you want them to be downloaded/ installed automatically or just notify.
If you're running a version of windows that includes group policy editor, it does. Given the way windows 10+ disregards if not outright changes settings, I wouldn't exactly bet my life or my PC on it anyways.
My specific point, at any rate, was that Windows does not respect settings regarding metered connection.