KDE neon is described as 'Ubuntu-based Linux distribution that offers a stable and easy-to-use platform, featuring the latest KDE Plasma desktop and application releases' and is a popular Linux Distro in the os & utilities category. There are more than 100 alternatives to KDE neon for a variety of platforms, including Linux, Self-Hosted, Arch Linux, BSD and Mac apps. The best KDE neon alternative is Linux Mint, which is both free and Open Source. Other great apps like KDE neon are Ubuntu, Debian, Fedora and Arch Linux.
KDE Neon and Kubuntu are about as close relatives as two Linux distributions can be. Both are Ubuntu under the hood. Both use KDE's recent and impressive Plasma as the default desktop. The difference? Kubuntu is updated when it's updated. KDE Neon is the same, except it gets Plasma-related updates quicker. (When they come out.) That's it. That's the difference.