Proper method for Docker Installation without a domain?

Is there a “correct” way to go about installing Seafile Server via docker when hosting in a LAN environment without utilizing port 80 on the host machine? I’ve been following the docker installation documentation, but I noticed that even if I updated the compose file port mapping to 8000:80, nginx in the container environment would not route traffic to seahub when I went to http://:8000/. I ended up with a 502 error.

By dumb luck, I went about trying to update the compose file setting SEAFILE_SERVER_HOSTNAME to :8000, deploying the compose file, stopping the system, then manually going into the /opt/seafile-data directory down to the nginx config file, setting server_name from <host network ip>:8000 back to just <host network ip>. After restarting the containers the server (miraculously) came up and was usable/functional.

The hackery involved in this leads me to wonder explicitly, what is the “correct” way to deploy seafile using the docker compose configuration when the host machine will be serving seafile on an alternative port, and will not have a domain name for nginx to manage the incoming requests? I managed to poke and prod my way to a functional config, but this is a pretty gnarly trap for new users, and I’m still not really sure why this worked, while an approach of setting the SEAFILE_SERVER_HOSTNAME to just the machine IP, and manually updating seafile/conf/ccnet.conf's SERVICE_URL to include port 8000 failed.