Correct. The device’s subsystem that handles the RAAT networking stuff has no way to communicate DSD streams or multichannel to the rest of the system. The USB/HDMI stuff has no such limitation in their platform.
We tried to get this limitation resolved during certification, but it was not possible. They are still investigating this for a possible future release, but no ETA on that.
I realize that while this is not ideal, the work done here and the Roon Ready support is a nice freebie for you Oppo owners.