DIAGNOSIS That's coil whine from the power supply circuitry, a common annoyance with the v3, not a sign of failure.
FIX First, swap the power adapter. Use the official Wyze one or a high-quality 5V/2A USB adapter and a known-good cable. Cheap or underpowered adapters exacerbate the whine.
IF THAT DIDN'T WORK The noise can vary by unit. If it's new and unbearable, contact Wyze support for a replacement under warranty—some batches are worse than others.
HEADS UP The noise is often more audible in quiet rooms. You can't fix it via software, and putting it in a case won't muffle it much.