The trouble with Windows' insistence on backing up is this: it has no way to tell which files in Documents, Music, Videos, etc, need to be backed up, and which don't. For example FL Studio puts a ton of files in Documents\Image-Line. Around three gigs. Most of those are provided in the installer, so it's crazy to use cloud space for those. Of all that, only Documents\Image-Line\FL Studio\Projects needs backing up, and possibly a few user-created presets lurking somewhere. And it is a similar story for much of my music software. Then there are many gigs of music files that I have backed up on NAS anyway, so no need to back them up to the cloud (and if I did, I'd blow my 100G cap).
But Microsoft in their infinite wisdom think it's sensible to just try and back up all that to the cloud, possibly using a free account with only 5G total, for 100's of gigs of data.