I’ve got Jellyfin up and running right now on a DS620Slim NAS and it’s running pretty good so far. I’ve seen a lot of people say they prefer Plex over Jellyfin. What are the main advantages to plex?
My experience with Jellyfin have not been great. The mobile app is just not working well enough
Plex has lots of customisation available (which I prefer) but is a little harder to get running in my experience. I'd say, install them both and see what you like most. Do start with Jellyfin as it's easy to install.