I am aware that Apple TV cannot pass-through Dolby or DTS audio and Infuse converts them to PCM. However it seems Infuse does not embed any metadata in PCM audio as MAT.
One of the most useful metadata in Dolby audio is (all DD, DD+ or Dolby True HD) dynamic range compression metadata. All modern AVRs supports dolby dynamic range compression information (under different terminology such as dynamic-range-compression, night-mode or auto-volume-limiter). I think AVRs with Dolby Atmos support, also support these metadata in PCM audio via Dolby MAT.
The same movie (mkv with Dolby True HD audio) played via Nvidia Shield sounds much nicer (specially at lower volumes) than Infuse/Apple TV 4k. I think Infuse does not embed any metadata in PCM audio. Someone has more info or thoughts regarding this?