You don't want a
paid Linux. You want a
paid Linux desktop-system - aka a "desktop environment software package" which support running on top of 3 most popular Linux
server distros: RHEL, Ubuntu Server, Debian.
The only reason I and a lot of other people use Linux on desktops is because everything we work on runs on Linux servers and we want the same OS on our machines that runs on the server (even if we also use virtualization & docker when needed).
Even if someone made a perfectly polished Linux desktop system I'd still use some Ubuntu Server with an XFCE DE thrown on top because I like developing on a system most similar to what my software runs on. Incidentally, if I need to develop Windows software, I develop it on Windows. Only exceptions to this are Android and iOS since I couldn't find any good enough dev env setup for these systems.
If you ask for a "polished Linux desktop not based on a server-Linux distro", you are putting yourself into a very narrow niche.... a niche too small be worth developing for :)