From what I understand, what happens is that when the software or the Dac does the first unfold, it expands the audio “container” to 88.2 or 96khz to have enough room for all the frequencies; but that doesn’t necessarily mean that the actual audio data goes that high.
In Roon, the signal path is much clearer than in Audirvana. The MQA file has embedded data that tells the DAC that the original recording sample rate was 44.1 or 48 Khz, so that’s why once the unfolded “Hi-res” frequency goes through the DAC, it cuts/downsamples the output back to 44.1/48 Khz as “instructed” by the MQA codec since it’s the original frequency that the material was recorded/mastered in the studio.
That is, UNLESS there is actually higher frequencies compressed within the file, up to 192 Khz, so in that case, it would unfold further or stay at least in 88.2/96. But in most cases, I find that all those Tidal MQA songs are encoded in 44.1 or 48 Khz, with 24 bit. Just a few are actually real 96 Khz.
Hope this helps, and I hope what I understand, is correct