The same here. I’m running Roon on Apple Silicon on all my devices. and just updated to Sequoia. The connected USB device was always working before, now I don‘t see it anymore in the devices list. In the system audio list it‘s still there. Any results yet?
After getting in contact with the Apple support we found out that the problems is located to the current user. With the current user my USB DAC was not working at all, neither on Roon nor as a system output. After creating a new user the USB DAC was working again with Roon and as system output. Eventually I tried the original user again, and suddenly the sound came back through this device.
So maybe this will help somebody facing the same issue.
Thanks so much for writing in - I did move your replies into their own thread for proper tracking purposes.
Can you shed a bit more detail around this? Was there any system differences between your initial user settings, and the new user you created on the Mac?