There's still room for improvement, but Linux gaming has come a long way in a short time.
I remember when Proton launched it was like magic playing games like Doom and Nier Automata straight from the Linux Steam client with excellent performance. I do not miss the days of having the Windows version of Steam installed separately.
I know that the vulcan-tools package has vkcube in it. Someone did make vulkangears as an example, along with some other examples, but I don't think its a published package in any distro repos so it'd need to be manually compiled to run it.