Where are you seeing the ads? I got rid of my old Windows 7 desktop PC two years ago and replaced it with a Windows 10 virtual machine under parallels. I have never seen any ads. Are you seeing them in Microsoft Edge maybe? I hardly ever use that, since it's a VM I only use Windows for some specialized software and do everything else in MacOS.
Now, I actually purchased a new copy Windows 10 when I setup the VM. So, perhaps that's the difference?