Windows 10 Update Disabler does what the name implies; stops Windows Update from running.
The app is portable but a bit tricky to run. You need to Run as administrator in the same folder you extract the file to get it working. Running the executable, even as admin, will fail. The easiest way to do this is to use ctrl+s on your keyboard, type in cmd and right-click on command prompt and run as administrator. Once completed, type in UpdaterDisabler -install.
While not the most user-friendly way to go about this, disabling Windows Updates is a niche thing that most people never want, nor have a need, to do.
Once completed, you should get a message if it worked or not.
To restore Windows Updates, follow the same steps and type in UpdaterDisabler -remove.
Windows 10 Update Disabler was not publicly tested, so there's no guarantee it will work. It's also not very user-friendly, but if all else fails, this may be what you need.