I wouldn't say they are reinventing the wheel. Putting a new set of rims on them, maybe...

"KDE Linux is an “immutable base OS” Linux distro created using Arch Linux packages, but it should not be considered an “Arch-based distro”; Arch is simply a means to an end, and KDE Linux doesn’t even ship with the pacman package manager."

https://kde.org/linux/

CatchyOS is great, been using it for months and been good overall. There is also garuda linux, it looks great too, only tested it for a little though, worth trying if you are in your distro-hopping phase: https://garudalinux.org

Have you tried KDE on Fedora? I'm very happy with it.

What exactly is missing from say, KDE on debian? I recently installed it for my family computer and have had zero qualms with it.