Hmm... I don't know of anyone who uses Plex for anything other than viewing their own media.
Generally when community-developed software starts looking for ways to monetize, that's when it's a good time for its users to start looking for alternatives. I saw some people on Slashdot talking about Jellyfin... has anyone here used it?
I started with Plex from the start when it was OSXBMC. Got fed up not having the ability to turn off transcoding at the server level (all my clients Direct Play but randomly didn't). So jumped to Emby a few years ago as they had an option to turn off transcoding at the server. Got fed up of premium feature pop ups, shady dev behaviour and found Jellyfin. It does everything I need.
Been running it for about 6 months now with very few issues (surprising as I only initially installed it to test, thinking it wouldn't be anywhere near ready but having the open source Emby code as a starting point gave it a decent leg up).
Unless you need something specific that Emby provides that you can't do with a Jellyfin setup I would switch.
The main issue you may have is with specific clients, namely smart TVs and Roku (although on my LG OLED I use
Screenplay - not pretty but plenty functional).
I don't really care about closed and open source etc. But the behaviour of the Emby dev was pretty crappy. Not the whole story, but the start:
After the news that Emby server is now proprietary, with only some plugins being open source, a free software fork of Emby was created, called Jellyfin.
www.linuxuprising.com
Jellyfin has also started fixing some of the custom Emby code base with open source alternatives such as the implementing Kestrel, moves like this should improve the end user experience in the long run:
Jellyfin 10.3.0 Release Notes
Haven't used it and you may have a hard time finding people here that have... they don't currently support iOS or Apple TV. The server can run on a Mac, but that's an expensive option. Jellyfin is a fork of Emby.
They don't have to support iOS or Apple TV - as others do.
I use MrMC (Kodi fork - it plays everything) on my Apple TV with Jellyfin. Currently this piggybacks off the Emby service but there are plans to break this out as its own Jellyfin service (as the Jellyfin code will inevitably diverge from its Emby roots).
For simpler setups Infuse works over DLNA. But personally not a fan of the UI.
I run the server on a lowly RPi 2 Model B which handles everything I've thrown at it, up to and including UHD Blu-ray at about 20GB per movie.