Thanks for your answer, @Andykong.
Yes, I had observed the requirement to have a headphone connected. Without one, the N6ii status bar would display a rate one big step lower. Saw this for both the A01 and T01.
Regarding MQA, it seems I still need to understand much more than I do now - IF MQA lends itself to being understood by the general public at all. Maybe the point is in ”full decoder“ versus ”renderer“.
Now, on a related note, I am left with these questions, dear @Andykong: What Settings are the correct ones for using the N6ii as a USB-DAC with Roon (on Windows in my case)? In particular, what Settings regarding the MQA capabilities? And what am I supposed to see when looking at the Signal Path during MQA playback from Tidal integrated within Roon? And even though I didn‘t use it yet, I would also like to know what Settings need to be dialed in in the original Tidal Windows app? When running the N6ii as a USB-DAC on Windows, it might also be interesting to look at the status display provided by the Cayin (Thesycon) driver; off-hand I‘d guess it would show 88.2 or 96 kHz when Roon runs as a first-unfold MQA Core.
Sorry, I am not a ROON user, and Cayin has not tested our product for ROON compatibility, nor submit our product to ROON for testing, we can't provide any guideline or suggestion regarding ROON usage.
I was under the impression that MQA will not output bitstream beyond 88.2/96 kHz over USB or S/PDIF, So your guess is a sensible prediction IMHO.