Hello @Niklas_Nilsson,
We spoke with the development team regarding this issue.
Roon supports audio devices with 2.0, 5.1, and 7.1 channel layouts.
Thus, the behavior you are seeing with the 4.0 audio device is expected behavior.
You can try using a virtual audio device to expose a 5.1 or 7.1 device to Roon, and then route the virtual audio output to your focusrite. We cannot “officially” support this setup, but if you would like to experiment it may work.
An example of this type of applications is VB-CABLE: https://www.vb-audio.com/Cable/#DownloadCable
-John