My setup is a conglomeration of a quite a few different pieces; but they are not all required. I'd encourage you to explore, start small and expand into new pieces/areas when you feel comfortable. I started this ~8 years ago with basically 0 knowledge of hosting web services; and just built up the knowledge through exploration over time.

If all you're looking to do is watch movies, and you're happy to play the downloaded media directly on your pc (or move the files around manually, just like manual torrenting); the only piece you need is Radarr.

Once setup; You tell it what movies you want to watch, it searches for those using the indexers you've given it (YourBittorrent, TPB, and BadassTorrents for example), choses the best results out of them all based on things like upload date, seeds, quality descriptors in the title, etc. Then passes that to your torrent/usenet client. Finally it will rename and sort the files into nicely organized media folders for you, once the download client has marked it as complete.

https://www.stremio.com/

https://torrentio.org/

It's complicated to get set up. Once done, it makes everything very simple.

The three of them are all pretty similar, achieving the same goal; whatever works for you.

I've never had an issue with Ombi, so I've stuck with it. I actually use Emby instead of Jellyfin, so Overseerr isn't an option, and I've just not had a reason to try out Jellyseer over what's already setup and working.

Prowlarr is definitely a good recommendation. I used Jackett for the longest time; but being able to modify indexers in one place, then have it propagate to the rest of the stack is so much nicer. It lists a ton of indexers to look into too, if you need more.