Step 2: Logging into the KDE Plasma Session on Ubuntu. Proceed to input your credentials and log in. You should see “Plasma” as the default session type in the top left-hand corner of your screen. If it’s not already selected, click on the session drop-down menu and choose “Plasma”.
From dir /usr/share/xsessions move all *.desktop file to another directory (unnecessary_env, for example) and leave only one you need (in my case - xfce.desktop): $ ls /usr/share/xsessions xfce.desktop unnecessary_env/. After logout/reboot XFCE will be loaded by default. Note!
1. Install packages. Open a terminal and run the following command to install those packages. pacman -S --needed xorg sddm. pacman -S --needed plasma kde-applications. When asked to select a package, press enter for default selection. If you are unsure, choose the following options when asked on the screen. I tried it for a few minutes, and thought I would keep it alongside GNOME. However, then I realized that KDE Connect from Plasma was interfering with the functionality of GSConnect in GNOME, so I tried deleting KDE with sudo tasksel remove kubuntu-desktop. While watching the process, I realized that it was deleting a lot of software that it