I would try flashing an Ubuntu (or Kubuntu for KDE) or PopOS iso and booting that to try, they both include the proprietary Nvidia driver. This might be a Cinnamon issue or a Mint issue, trying a different distro helps you narrow down the possible cause.
This is probably a pretty unpopular opinion but I would never recommend anything but Gnome or KDE to a new Linux user. Those projects just have so much more development focus on them then all the smaller ones, it just makes sense to default to them for maximum ease of use and compatibility.