Welcome to /c/piracy
No netflix or streaming services landlubbers allowed, this is pirates territory.
What you're looking for is Jellyfin + Sonarr (TV Shows) + Radarr (Movies), you can also add more optionals like Bazarr (Subtitles) etc. (they're called the 'arr' programs).
Easiest way to set this up is a Docker container for each app and then configure them and connect them together through the UI. There's also an .ISO for normies called Umbrel that makes it look like an App Store if you can't be arsed to set up a home-server yourself.
Thanks! I will most likely go the docker route. Now, gotta pick a NAS to buy...
I'd suggest building your own and using truenas scale as it has a bunch of bundled docker images you can run with minimal effort.
I've tried setting this up a few different ways, and I could never wrap my head around docker. The easiest way I've found is something called Swizzin community edition. It's basically just a script you run on a fresh Ubuntu server, and it walks you through a wizard to install whichever of all the relevant apps you want. It configures all the reverse proxy settings or whatever for you. I'm running it on a vps, so I also have a domain name pointed to my server IP.
There are, of course other projects that do pretty much the same thing as swizzin, and some even are docker based, if you really want to go that route.
One thing you want to keep in mind if you use a vps (or even hosting at home, depending on your ISP), is configuring a VPN for your torrent traffic. It can be tricky ensuring that your IP doesn't leak and get you booted from your connection.
As far as the VPN goes I have a ProtonVPN subscription, and I tested it out and my IP wasn't leaking.
I don't use Jellyfin in particular but I've got something set up to achieve what you have outlined.
Sonarr and Radarr have my watchlists for TV and movies respectively. Based on those watchlists, quality settings, and online release calendars they search torrent sites for new releases. If you want to subscribe to a Usenet service they work on those as well. Once the item is available the torrent file or magnet link is sent to a torrent client. Once the file is downloaded Sonarr or Radarr move it to a directory where Plex can index it and add it to the media library.
There are a few weird moments where it doesn't work, but in general a new episode is available on my server within an hour of its original airing having finished, and I don't have to do anything.
It's really handy to run these on a seedbox or VPS. For local installs there are a bunch of dockerized versions of these services which makes it relatively easy to set up.