Container Attached To Network, Network Inspect Shows No Containers

I am simply trying to connect a ROS2 node from my Ubuntu 22.04 VM on my laptop to another ROS2 node on another machine running Ubuntu 18.04. Ideally, I would only have Docker on the second machine (the first machine runs a trivial node that will never change), but I have been trying using a separate container on each.

Here is what I am doing and what I am seeing when I inspect:
ssh into machine 2 from VM 1.

Please click here to see images corresponding to the following steps I took (im a new user cant embed)

A: start up network from machine 2.

B: start up container 1.

C: successfully attach container 1 to the network.

D: Confirm the container lists network.

E: Check the network to see container.

I am relatively new to Docker, so I could be missing something huge, but I have tried all of the standard suggestions I found online including disabling my firewall, opening a ton of ports using ufw allow on both machines, making sure nodes are active, etc etc etc etc etc.

I tried joining the network from machine 2 and that works and the container is displayed when using network inspect. But when I do that, then machine 1 simply refuses to connect to network.
F: In this situation it gives an error.

Also, before trying any docker networking, I have tried plainly pinging from VM1 to machine 2 and that works, both ways. I have tried to use netcat to open an old-timey chat window on port 1234 (random port as per this resource) and that works one way only. I can communicate both ways, but only when machine 1 sends the initial netcat request and machine 2 listens. When machine 2 sends request and 1 listens, nothing happens.

I have been struggling to get this to work for 3 weeks now. I know it’s something stupid, I just know it. I don’t even think it’s Docker’s fault. Any advice would be incredibly appreciated.