If you want passthrough for TrueHD/+Atmos and dts-HD/:X audio when watching 4K HDR video you’ll need to get a Nvidia Shield Pro. It is the only Plex client that plays 4K HDR video and passes those audio formats. Do not purchase the non-Pro “tube” model. It has problems with high bit-rate media such as 4K HDR rips.
The AppleTV 4K does not passthrough TrueHD or dts audio. This is an Apple restriction.
The Plex SmartTV apps cannot passthrough lossless audio such as TrueHD or dts-HD, even when connected to an AVR via HDMI-eARC. The TV manufacturers do not support the capability. The restriction applies to all apps, not just Plex.
See this post for additional information:
