The device settings doesn’t show the 7.1 headphones as an option.
The only options for sound output are
Speakers (2-Realtek(R) Audio) and
Headphones (2-Realtek(R) Audio)
Neither of these work for the 7.1 software.
Additionally the headphones sound awful, just woefully inadequate, there is no substance to the sound like the Bass, Mid, and Treble have all been turned right down to zero