[Karellen]

if they can force using NFO data.

It doesn't work like that. Kodi, nor any skin, will open an nfo file for data. nfo files are used only when running a scan.
Anyway, as you have been advised already, the data in the nfo file for audio codec is not compatible with Kodi.

[jjd-uk]

Note this will change as soon as we've updated the ffmpeg version Kodi uses which is being work on for v22. Once update is complete Kodi will be able to recognise Atmos and DTS:X audio within files and consequently it will become a valid value to have the the streamdetails db table, and thus it will also become valid for use in a nfo.