[Soli]

@Soli: What about internal processing? Volume or the OS doing mixing, cause it assumes it is just normal whatever PCM content?

It highly matters that a playback programm does NOT touch any data ... if the stuff it transmits is passthrough. Nothing of the stuff you say will survive an internal volume on the decoded float data.

Yes, basically you will get DTS audio without "passthrough", but only because AVR receivers looks at the pcm stream itself (because S/Pdif doesn't tell anything about the format, only if it is a bitstream or pcm). So yeah, as long as Kodi and Windows volume is at max and you use wasapi, or alsa and not pulse, then you might get DTS from 2 channel pcm files, which can be wv, wav or flac, etc. This is how I understand it, without having any deep knowledge of Kodi subsystem

Random noise from raw dts it at least -12db down, so your speakers should be good! But yeah, I can see lots of scenarios that the "fake passthrough" will lead to unpleasantness..