How to start docker-desktop as root

As the guide says in the section Launch docker desktop, start docker desktop with systemctl --user start docker-desktop.

But, how can I start docker-desktop as root? I need to use container with my gpu, so I have to run the container with sudo or as root. How can I run a container on docker-desktop as root? I tried the command sudo systemctl start docker-desktop, but it said that Failed to start docker.service: Unit not found. Or I tried just sudo docker run hello-world (just for an example), it said that docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?..

So, HOW CAN I RUN A CONTAINER ON DOCKER-DESKTOP AS ROOT?
Could anybody help me? plz

some relative information about my device:

  • OS: kubuntu 20.04 LTS
  • Version of docker-desktop: 4.15.0-amd64