You can and should setup your Windows 10 computers not to update when they are on a “metered connection”. It is easy to do. A simple internet search will give you all the details you need to set this up in a few minutes. It is one redeeming feature that Microsoft included in this bane to computer OS’s.
I have my computer set to metered connection and I also downloaded a program called Microsoft Mini Tool. It will check for updates and allows me to pick and choose the updates I want and ignore others. Which Windows 10 will not let you do, it downloads all of them, whether you want them to or not.