LG UltraFine 4K audio issue with MacBook Air M2 running macOS Sequoia

MacBook Air 15" M2 (2023)

OS: Sequoia 15.1.1

Monitor: LG 32” UHD UltraFine 4K with USB-C and Built-In Speakers

Cable: Apple Thunderbolt 3 (1 meter)

Around the time I updated to Sequoia, the audio on the monitor stopped working. LG HDR 4K is a selectable output in the Sound menu and control panel, but the volume slider becomes "greyed out" with no sound. Internal speakers work fine, as do the external speakers with a Windows PC.

Oddly, in Utilities > Audio MIDI Setup, you can get the test sound (white noise) to play in each channel with the Configure Speakers button.

Tried without luck:

sudo killall coreaudiod

[Re-Titled by Moderator]