I have been wanting to try out openSuse but have never tried or used a RPM based Linux distro. I am coming from using Debian/Ubuntu and distros based on those distros. I just wonder how user friendly is openSuse compared to Ubuntu or Debian? And how well does openSuse support gaming on Linux?
openSUSE has about the same level of gaming support as other distributions. To get better at using it, I recommend checking out the documentation.
In my experience with Tumbleweed it works really good (you should definitely use it over Leap in this usage scenario to benefit from faster updates). Steam, Lutris, gamescope and all those goodies are readily available from the repos in addition to Flatpak and work as you’d expect. The only time I had some initial issues was when setting up Sunshine to stream to Moonlight on my smartphone, doesn’t seem to be distro-specific though. 
Also works great on my gaming Laptop, the wiki’s explanation of how to install the (notoriously awful) Nvidia drivers worked right away.
It’s no doubt better than Ubuntu for gaming, hands down. However if gaming is your only or at least primary use-case perhaps a distro like Nobara is more for you given it comes with all the tiny bits and pieces you that might be useful already in place.
However with OpenSuse you got more people to ask for help, and the Software Search is also really handy. Kinda like Ubuntu’s “PPA” repos. Also YaST really makes the distro stand out, making almost everything available via GUI (in addition to the common system settings of KDE or Gnome + Gnome Tweaks.
I’d definitely suggest you giving Tumbleweed a try.