tl;dr the plex app has strange unnecessary hard limits (4Mbps, 2 channels, 1920x1080, …) and anything outside of that it forces a transcoding.
The media plays fine directly via DLNA.
There are some workarounds.
Would be nice if Plex added a button to the server so we could have it lie to their own app, but I am getting to the point of just dropping Plex and sticking with DLNA which works and is predictable.
