If you’re set on Nvidia, I recommend Pop OS or Nobara. Pop has a separate image that preinstalls Nvidia drivers. Nobara has a built in tool to download and install Nvidia drivers on first launch. Of the two, I’d probably go with Nobara (I’ve been using it for a year or so, love it) because not only does it have that tool, it also has an official KDE version, which it sounds like you’d prefer. You could install KDE with Pop, but I’ve done that before, and it creates a bloated nightmare of conflicting apps.