Radarr helps manage your movie library, Sonarr and Lidarr are the same for TV shows and music, respectively. Prowlarr will integrate with all three to search your favorite torrent tracker or NZB indexer for content added to your library. They'll integrate with many popular torrent and usenet download clients to automatically download and import the content to a Jellyfin library. When paired with a request service like Jellyseerr, you can hit a single button to request a movie and have it show up in your library 10 minutes later.
It takes some patience to configure everything, but there's some really great guides out there. Feel free to drop me a DM if you have any questions!