As others have noted this is not true.
When stating a device’s compatibilities with audio and video codecs, we are referring to native support. If bandwidth is not an issue, and Plex has to transcode the codec to play on the device, that device does not support it.
For those of us that rip Blu-Rays and want to Direct Play the content without transcoding, the Nvidia Shield is our only device option for full HD Audio and Dolby Vision (Profile 7) support. Though it still has some issues with some movies which has pushed me to start using Zidoo.
A big selling point of Infuse has been their longtime support of HD audio formats found on Blu-Ray remuxes.
I did a semi-technical write up of the state of HD audio on the AppleTV a few years ago (for now this information is still accurate):
