Most of them won't really do anything about what you upload unless somebody specifically reports it. I would still recommend encrypting anything important like legal documents or whatever but if you're worried they're going to get at you for a pirated movie or something like that I promise you they aren't, unless you're sharing that around with a bunch of people
I can confirm that at least both Dropbox and Google drive will not throw a fit about that kind of material as long as nobody reports it
And if you're really paranoid just throw them in a password-protected raw file and set it to encrypt the file names as well and then they pretty much can't do anything about it
I mean I've literally never had windows fail for something that wasn't ultimately my fault but still to keep safe I just keep my main OS and games on my M2 SSD and everything else goes on regular SATA SSDs or HDDs in my system that way if somehow windows does get completely fucked to the point where I can't fix it I can just wipe that SSD and reinstall Windows and its games without worrying about my data on the rest of the drives being affected
And of course all my important files are backed up to my NAS and/or Dropbox