Plex is the most worked on solution out there, runs on Windows, Linux and Linux headless. For the automation of stuff then looking at suff like radarr and sonar alovk with tracktarr and jackett foe the trackers, along with a torrent client. There is also jellyfin as a media client, it’s more open, but getting users onto it could be more problematic as it isn’t as straight fwd from what I hear, haven’t used it myself though.

With the advent of self hosted streaming services and the arr services the option is even easier now. If 1 in 20 ppl are motivated/tech savvy that’s 20 streaming products not being paid for.