no prob. that's correct, yeah.
many devices don't support dual layer DV profile 7 like ATV 4K, Fire TV 4K, Android boxes, etc. also mkv only recognizes elementary video tracks so if and when we get software to either convert dv mp4s, or rip discs directly, to single layer mkv remuxes it will allow for dv with hd-audio. until then it's basically just for added compatibility.
there is plenty of software that can extract true-hd and atmos tracks. the problem is the limitation in the mp4 container, as it supports eac3 audio at best. yusesope can manipulate them further to push lpcm 7.1 (and dts-hd perhaps?), but atmos seems like a no go.