Just to make sure I understood your question. The gadget has an I2s HDMI output which is connected to the D90 MQA I2S HDMI input. My Oppo 93 has 2 HDMI outputs. Any output will do. It's connected to the gadget HDMI input and the HDMI output is connected to my TV so that I can see the SACD details like album, song titles, etc.
Edit: I wrote an email to Topping in China regarding the issue. They think the gadget is not compatible however I cannot be sure until someone on this forum who uses similar devices can share it with us. I believe that the CPLD chip is faulty. The PCM/DSD "depop" switch is faulty or not capable of switching quick enough which is why I said in my previous comment that the D90 panel went fuzzy for split nanosecond trying to output in DSD. Like I have said, the D90 is always displaying PCM by default and the resolution is blank until it detects a DSD signal, the panel went fuzzy and display DSD and the resolution is shown as 2.82Mhz. But at that point in time, the buzzing sound is heard at the very beginning of the 1st track. At the end of the last track sometimes I can hear a buzzing sound but not always.
Using the same gadget, I play SACD via coaxial or optical. I have no issue whatsoever however the panel will display PCM at 88.2Khz only.