I can recommend the dietpi OS; it is a minimal os that comes with a package manager for installing containers for things like radarr, sonarr, deluge, and jellyfin, which will allow you to download/watch movies(find on radarr, download with deluge, watch on jellyfin) and tv shows (find on sonarr, download with deluge, watch on jelyfin) in a fairly autonomous way. Its a bit of setup if you havent done it before it might not be for you but once its running its fairly seamless.
I threw this on my server to see how it runs, I’m not able to see any of my library( I think this is the connection to jellyfin) or any way that it connects to my sonarr/radarr services? I tripple checked that the api keys are correct but I’m still not seeing anything. I saw that someone else said that it does browser caching and I have a large library so maybe that is the issue. I look forward to seeing how this project progresses because I host all of these services and it will be nice to have one place to go for them.
It depends on your distro but there is a NOPASSWORD option in some that you can add to a sudoers file. Without knowing your system its probably best to use your search engine of choice to look for answers to that but be warned that it is a security risk.
Dang I wish I knew about this a month ago, I just built a NAS myself. Thanks for the link!