Keegen

Honestly anything with a non LTS release schedule will be fine. So long as you keep a relatively recent kernel and GPU drivers it pretty much doesn’t matter. You can go for a rolling release like Arch or OpenSUSE Tumbleweed or a staged release like Fedora. Even Ubuntu or it’s derivatives are fine so long as you stick to the yearly versions and don’t have a particularly bleeding-edge hardware.
My only advice is stick to the popular stuff. This applies to both distros and desktop environments. Much easier to troubleshoot things and find help and they have more people using them, which usually means the experience is more polished and bugs get fixed faster.

You’re using an RDNA2 card so it’s possible your low FPS is caused by this issue. I would try this fix that was mentioned in the comments under that issue to see if your performance improves.

Glad to hear it! Enjoy your Linux journey!

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.

Using the open source driver with Nvidia is a bad idea, your card is locked at the minimum clock speed and it’s general quality is not comparable to the proprietary driver (this is purely because of Nvidia’s hostility to open source, not due to any inabilities of the developers of Nouvea.)
I’m gonna assume you are using the default desktop environment of Mint which is Cinnamon. Have you tried booting a different DE, or even better, a different distribution with something like Gnome or KDE to see if the issue persists?