KDE neon has Docker images which are great for easily testing out KDE software built from Git master, Git testing or releases without touching your host system.
The images have just been updating to use KDE neon on the new Ubuntu LTS base 22.04 (jammy).
Xephyr -screen 1024x768 :1 &
docker run -v /tmp/.X11-unix:/tmp/.X11-unix kdeneon/plasma:unstable
or single app
docker run -v /tmp/.X11-unix:/tmp/.X11-unix -e DISPLAY=:0 --security-opt seccomp=unconfined kdeneon/plasma:unstable dolphin