Bazzite, it’s based on immutable Fedora. But it made sense for my use case because it’s one of the more consistent at working out of the box with Nvidia graphics cards and I wanted the gaming stuff, but Plasma should be more or less the same everywhere. I’m not sure which version of Plasma it’s running but Bazzite is generally pretty up to date with everything but I can’t check right now.

Don’t sweat “what distro” so much. All the major distros offer the same desk tops. So pick a distro you like and just download the KDE Plasma spin of it and enjoy.