Wireless does not degrade the signal, but the answer to your second question is more complicated as it depends on which components you are talking about. DACs vary widely in how well or poorly they implement USB, and wireless servers also are not all the same.
Wi-Fi Fidelity?
Any degradation of signal (i.e.: loss of fidelity) when sending that signal via wireless? My only physical connectivity option from laptop to DAC is via USB – unfortunately, the DAC is not HDMI capable. Which would provide the best signal transfer, the laptop + DAC (via USB), or the laptop + Wi-Fi router + Wi-Fi server +DAC (via coax)?