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>...