(The "Windows" slices of the pies are entirely made up by Baldur's Gate 3, which also runs well over Linux)
There's a bunch of other things, like HDR; I don't have a HDR monitor so I can't say what people are missing, but I tried to mess with it in my pet-project game engine and vkSetHdrMetadataEXT just does not exist at all, and I don't know what library or Vulkan layer could provide it.
It matches with what I've heard around, although apparently KDE supports it now?