"obscure Emby"... You don't get out much, do you.
Emby is a direct competitor to Plex, and its better. It doesn't require and internet connection to work, doesnt force signup, its completely self hosted if you want. The dev is responsive, bugs are fixed quickly.
It does have subscription options if you want, none are required for full functionality.
Emby is not FOSS, but neither is Plex.
no. Jellyfin aims to be totally open source.
Emby is not, and the reason it works better. They pay the licenses for mp4 etc. earn it back from those who support, but it never was truly open source.
Jellyfin is open source, and that is the reason they have "problems" (licensing issues, that you have circumvent if you look hard enough).
For set and forget, Emby and Plex are the choices. Emby does not have a bullshit money making agenda, and is the better option - currently.