To remove docker from Flatcar entirely - by replacing the docker torcx with one that calls podman instead. You will also need the podman sysext from My Repo or jepio's Repo
./build.sh
./install.sh
And reboot.
Once you reboot, docker should call podman. It'll tell you that too, by putting Emulate Docker CLI using podman. Create /etc/containers/nodocker to quiet msg. on the console.
Calling something like dockerd from the command line will tell you The current torcx profile did not install a dockerd program..