Tumbleweed is fine for gaming. I daily drive it for three years now and cant complain much.
Just as a note, if you cant connect to external devices check the firewall first, you might need to open ports. YaST has a module for that, no need for Terminal foo.
Dont go and use too many OBS Repos (via opi), it is possible to run into conflicts sooner than later.
If you cant find your desired software check flatpak or appimage, distrobox is another option.
Xfce, i just like it.
pop-shell and something for desktop and tray icons, i dont remember those names.
openSUSE Tumbleweed, it just works for me.
That it i guess 🤔