Audio very quiet in Oculus headset, but works fine in Simulation

Development Audio
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3

Wow, this sure turned out to be stupid, but I eventually found this:

[VR, Oculus, UE5.3, Audio, HDM] No audio on headset, only on PC - Development / Audio - Epic Developer Community Forums (unrealengine.com)

And that was it. PreviewVR was using its default audio output, instead of switching to the Quest headset, which is…ummm…pretty lame, but whatever.