I like Debian a lot, and Mint seems fine too, but I don't like the styling, or Cinnamon really. I use Fluxbox (WM only, no DE) with a bunch of tiny customizations.
The main reason I picked it is that I like to tinker and she doesn't, so I think that Cinnamon will be the easiest for her coming from Windows 10.
We both have AMD GPUs (and she has a AMD CPU too) so I haven't had to deal with Nvidia headaches.
I like the glacial updates so things don't break as easily. I don't want to spend hours fixing a system (hers or mine tbh) unless I have to. For anything that I need the latest features for, there's usually a repo I can add to Aptitude or a Flatpak.