I have not used Plex in years, however, just the fact that Jellyfin is FOSS is enough for me to want to use it more. I am not sure what features Plex has that Jellyfin doesn’t, but, it does everything it can do really well. Honestly, just throw it up next to Plex and see how you like it. Installation is a breeze, at least with Docker.
Personally, I like it way more than 3. I could never get into the older games (including 3). Others say it’s a “reskin of 3” which I think is kind of ridiculous.
The story so far is actually pretty intriguing. I mean, it’s not mind-blowing, I’m pretty sure of what will happen, but it’s still good for a game in this genre.
Replayability is really endless, but, I don’t know if I’d say it has more replayability than the older games, it just may be more replayable for you if you like it more.