unix:///Users/greg/.rd/docker.sock

As per my previous question... can anyone confirm that RD docker is ONLY available from this context and not via ssh?

The docker port is not exposed over TCP, only as a Unix socket. You will have to forward it yourself over ssh with something like Forwarding the Docker Socket over SSH | by Drew Erny | Medium

@fast-garage-66093 that was exactly what I was looking for, thank you !!