@Audio_Guy I just tried out a few possible ways of getting 3D to work with a Pi and the results are great.
First the bad news, for some reason Plex embedded (based on LibreElec) doesn’t have 3D MVC enabled… why I don’t know, it shouldn’t be hard for the devs to add the option since its built into the underlying OS.
What does work is using the official Plex add-on for Kodi or the PlexKodiConnect add-on. The official add-on can be directly booted into and works just like any other Plex app, the other method imports your Plex server content into the default Kodi UI.
Both methods are able to play back full frame packed 3D and allow DTS/DD 5.1 pass-through. The only thing you don’t get is HD audio (DTS-HD, DTS-X. True-HD, or Atmos).