This was much harder than it should have been. If I were using the Docker Engine instead, it probably would have worked with only a few steps. But I like Docker Desktop, and I want to stick with it. This post explains how to run GUI applications in a Docker container on Linux, and forward the X11 display from the container to the host.

No Dogma Blog (Bryan Hogan)

A step-by-step guide for running GUI applications inside Docker Desktop containers on Linux with X11 display forwarding to the host. The key insight is using socat to bridge TCP port 6000 to the host's X11 Unix socket — a workaround required specifically for Docker Desktop (as opposed to Docker Engine). The guide covers building a Dockerfile with X11 dependencies, running socat, granting X11 access with xhost, and launching the container with the correct DISPLAY environment variable and host networking flags.

Docker Desktop Linux X11 Forwarding from Container to Host