Those are dependent on the relevant torrent being available and seeded
Jellyfin/Plex and Radarr/Sonarr + Usenet, you’ll have said file once downloaded for as long as you want, but requires considerably more storage space and torrents suck for older, more obscure stuff. Usenet doesn’t depend on seeders, and the big boys have something like 15+ years retention and you’ll always download them at full speed (no tons of seeders but slow upload speeds to worry about either)
So it’s a matter of personal preference
As far as I know, there’s still a strong but small community on Usenet for discussions still
As far as server/desktop stuffs, many have had decent success running them on things like old laptops and raspberry pis to decent success. Won’t be as powerful, but if it’s just you and a spouse and maybe kids or something it should be just fine