Nvidia Shield 2019 Pro ← HDMI → Marantz AVR ← HDMI → Sony TV
Note: There are several different Dolby Vision profiles. No one device supports them all, including the Shield. Plex is at the mercy of the device. It if does not support a certain profile, there is not much Plex can do about it.
Read [INFO] Plex, 4k, transcoding, and you - aka the rules of 4k
TV based apps cannot pass lossless audio such as TrueHD, even over HDMI-eARC (no known TV from any manufacturer supports this capability).
Does not support TrueHD + Atmos passthrough (Apple does not permit TrueHD passthrough). Audio will be passed as PCM 7.1 and Atmos information lost.