Jamie, Here are my responses to your questions.
Yes, I double-checked more than once that the input on the DAC is set to USB when connected to the nucleus.
Yes, I have tried a different USB cable.
No, I don’t have another endpoint but I plan on taking my nucleus down the street to the dealer from whom I purchased to see if I can hook up one of their endpoints just to double-check or further diagnose what’s going on.
Here is a screenshot of the device set up for the DAC. Hopefully I captured everything you need?