I don't even know if that's being maintained. I couldnt find anything on docker hub. It does look like this one is maintained though https://blog.pixelfed.de/2020/05/29/pixelfed-in-docker/
Maybe give that one a try. It seems like you are already using his image anyway. Also it seems like the command to run for the worker is different in his image.
If you have issues with that setup, feel free to post what issues you having.
Technically you don't really need to setup a bunch of networks unless you are trying to host this or something, which I wouldn't recommend docker compose anyway. So, if you wanted to keep it simple, you could just the default network.
Another note, while zknt/pixelfed does exist on docker hub. It was moved to quay, so continue using that image.
Not sure what pixelfed is, but you yelling I need help doesn't really help anyone. What problems are you having exactly. What image are using? What commands are running? What have you tried?