Desynth is possible. The regular NQ only gives Saruta Cotton, but I got 3 different HQs: 2x Wool Thread, 4x Silk Thread, 1x Gold Thread. The last one I only got once out of around 20 desynths so far (sorry, didn't really keep book on the statistics). The numbers are not the number of HQs but the number of threads returned from desynth.
I tried all the desynths between skill levels 60 (which were the expected desaster) and 72 (which I am now)