In reply to <a href="https://www.debugpoint.com/upgrade-kde-plasma-6/#comment-5794">Paul</a>. Try after a week. The first point release is now out. Should be stable within a few days...
Today 6 Mar EndeavourOS automatic update to plasma 6.0.1, but switch to Wayland :-(...
I clean installed Neon User 6.0 and found it quite buggy. My advice is to wait a while. Okay for clicking here and there and showing a few menus etc, but some of the underlying infrastructure does not marry well with existing apps. My first Neon User 6.0 install attempted to encrypt the disk, but that was a complete disaster. Neon 5.27 and Kubuntu 23.10 had worked fine with that process. I tried a simple plain-vanilla install, which completed, but many other issues popped up. Even the error reporting did not complete. Take a breath ... wait a few weeks ... or maybe even months, unless all you need is basic browsing and a few simple apps. Cheers...
Regarding Arch: Plasma 6 in the official repositories <a href="https://archlinux.org/packages/?q=plasma-desktop" target="_blank" rel="noopener nofollow ugc">is not yet stable, but in testing</a>. Thus, unless the user has enabled the testing repositories – hopefully understanding what that entails, it's not quite as simple as <code>sudo pacman -Syu</code>...