The arr stack is for downloading media in an automated matter, for example sonarr will scan the inderxers you give them for the series you want and automatically download them. Then you can use a service like jellyfin to watch your media

this sarcasm or ya actually in the know?

I’ll be honest, only the first setup gave me some trouble as I was tackling docker compose too. After you gain familiarity setting up a new arr is basically copying the provided yaml service then filling in the envs with yours