bro, there’s one container for the app, and one container for postgres, the all doesn’t surpass 500 Mo of RAM… where do you except to host the database ? Sorry If I sound a bit rude but you can always edit the .yaml manually to only launch the app, the app will use SQLite then, or configure an external postgres database via env :)

There is already a non-piped docker-compose setup. The installer just downloads the compose file and env.example, and you can also get them manually from GitHub.
You don’t need to set APP_PORT. If it’s unset, the app falls back to the PORT var provided by Portainer. Just make sure APP_URL exactly matches the root path you’re using behind Nginx.
I know from a friend his deployment running fine on Portainer, so it should work with a standard setup.