NI S4 Sound Outputs

Am I right in assuming that you can’t route the Audio from Djay Pro to the fader channels of the S4?

So you didn’t actually answer my question about the audio routing.
I fully understand that the S4 needs to be in MIDI mode

still doesn’t work even though the s4 is set to midi mode

djay Pro is capable of using the built-in sound card of the NI Traktor Kontrol S4.

However, as the S4 is not an external mixer, an individual Deck to Channel rooting is not possible.