U3824DW, Windows 11, No audio over USB C-1 from a Latitude 7430

Connecting my Latitude 7340 to my U3824DW monitor from the laptop's USB-C port (Thunderbolt 4.0 port with Power Delivery and DisplayPort 1.4 Alt mode) to the monitor's USB C-1 port. The laptop shows the Dell U3824DW HD Audio Driver for Display Audio as an output device. However, playing audio or testing the device from the Sound Settings dialog produces no audible sounds from the monitor's internal speakers. I verified the internal speakers are turned on via the U3824DW menu. 

If I connect the laptop to the monitor via HDMI then the monitor's internal speakers work as expected. 

Any assistance getting audio to work over the USB-C cable appreciated.