I am not going to be of much help, but, as you, I tried all the settings listed in the manual, the updated info, questions on forums, etc., etc. I was never able to play DSD on windows, no matter what.
I hooked te uDSD to a Linux RPi3 and it worked flawlessly. I won't be using windows for the uDSD now, but I got really frustrated by the fact that I couldn't get the DSD to work, ever. It's a constant reminder that there is a functionality I can never take advantage of, even if I tried.
If you find a solution, please share. Thanks,
Rafa.