Try KDE Plasma Desktop As A Snap Package

Users wanting to try out KDE Plasma can now install the whole Plasma desktop as a snap. By using the KDE Plasma desktop snap, you're not making any changes to your underlying system, while also having the option of easily removing it.

The KDE Plasma Desktop snap is available as a tech preview "and should not be considered for production".

Available as a standalone application, the KDE Plasma Desktop snap can be installed on any system that supports snaps, no matter if the system was previously using Plasma desktop or not (it doesn't replace existing Plasma desktop).

There are currently some limitations like Wayland not working with this session. You also cannot run applications from the host system, though you'll see other snaps (if you already have some applications installed as snaps) in the menu, but running them won't work. apt / snap commands to install extra software don't work either. As a result, this is useful for testing purposes, and not to replace your current desktop environment, at least for now.

Install the KDE Plasma Desktop snap (takes about 1.1 GB of disk space) using:

snap install --edge --devmode plasma-desktop

Installing it from the command line is required because the snap needs to be installed in unconfined devmode. You won't find the Plasma Desktop snap in Ubuntu / Gnome Software.

The new Plasma Desktop session isn't displayed on your login screen by default. To enable this, you'll need to download a plasma-snap.desktop file and place it in /usr/share/xsessions/. To do this using one command:

sudo wget https://metadata.neon.kde.org/snap/plasma-snap.desktop -O /usr/share/xsessions/plasma-snap.desktop

After this, reboot (a logout wasn't enough in my case) and you'll find a new Plasma Snap option in the session list on your login screen. Login to that session to try out your newly installed Plasma Desktop snap. Expect to wait a bit until the desktop loads for the first time (you may see a black screen for a while).

Users wanting to remove the Plasma Desktop snap and the manually installed plasma-snap.desktop file can use:

snap remove plasma-desktop
sudo rm /usr/share/xsessions/plasma-snap.desktop

via blog.ubuntu.com