Keep having this problem when watching movies, using Mi Box S 4K with Android TV.. Netflix and Plex both have the same issue. Any way to disable the dynamic range so that I can actually hear the dialogue and not blow my eardrums out if music starts to play in a scene or a car chase happens?
Some say that this is a cheap way of creating a bigger 'wow' effect while the whole audio is being compressed more, for streaming purposes. A good test would be to compare the soundtrack of the same movie with Blu-ray and your streaming platform. And be sure to check if the audio format you compare it to is a lossless one (true HD, DTS-HD, Atmos). I haven't tested this myself so I hope to see your reaction and if there is a difference. Of course the overall audio quality will be WAY better, but will the effects/dialog balance also change? Maybe!
I don't suppose you're watching a Christopher Nolan film are you? He has notoriously bad sound mixing just like you're describing.
Some receivers have night mode that restricts dynamic range. There is nothing in Android TV that does it since it mostly just passes through the audio to the audio system. Have you tried the different DSP modes on your receiver. Maybe one of them may help. You could also try turning off passthrough on the Plex app so the server always transcodes the surround sound to stereo. That may give a better effect.
As far as I know, most Android TV devices with Android 9 have a Dolby sounds or something similar where you can select between "Line" and another option I can't recall right now, but I believe that's for the analog audio output, with digital connections you need to set that in your receiver.