[ashlar]

Not getting any good vibes from that for sure.

On the contrary, FernetMenta clearly stated that a binary add-on for an extra video-renderer could be possible. The real problem is that I'm not sure if that could happen without madshi involvement.
Not being a coder I don't know if it would be possible to create the correct interfaces *in Kodi* to speak with madVR in the language it expects, so to say. Or if madVR should change somehow.
Then there's the point Warner306 raised, regarding HDR playback needing LAV video decoder to properly work (if I have gotten that correct, that is). But LAV comes from FFMPEG, so I guess that one could remain hopeful that in the feature these features might move upstream (if that's the correct way of saying "LAV functionality could be included in FFMPEG main codebase).

madVR being closed source, NGU being proprietary, instead, is forever out of reach, unless Kodi finds a way to "speak to it".