Using the iFi ASIO drivers I can get DSD512 from the Gryphon.
To be clear, after the ASIO drivers are installed the Gryphon will show up twice under Roon Settings>Audio.
You’ll want to enable the ASIO one.
As far as settings go: If you select the other xDSD device that Roon identifies for your audio device (I’m not at my computer right now so I can’t remember which one it is - Diablo maybe?)
These settings are also correct for the Gryphon.
As an iFi user just want to point out that on a Roon official blog [1] posted on October mentioned three iFi product including the xDSD Gryphon are Roon tested. However, none of them are either listed in the Roon partner page [2] or the Roon software iFi products selection interface at this moment.