We really love the Direct Steam DAC and we’re hugely excited to work with PS Audio on the integration of our RoonSpeakers streaming protocol in the future.
That said, right now I believe the Direct Steam uses UPNP for network streaming, which is not supported in Roon. Danny discussed some of the reasons here:
https://community.roonlabs.com/t/whats-wrong-with-upnp/2101/3