Definitely no whine coming from mine.
The Studio Ultra is about 60cm away from my head, I can hear the fans as just a dull whirr in the background, it's not completely silent. I didn't expect it to be silent.
It's probably exaggerated a bit by my desk layout, it's in an alcove under a shelf.
However, I then set up the free version of Macs Fan Control and configured it so the fan is at the slowest speed until the temperature hits 40°C. With that reduction in speed from 1315rpm down to 1100rpm, it's silent. I can't hear the fans and the noise app on my watch shows no difference whether it's on or off (I did this test in the early hours of the morning where it was utterly silent in the house and in my shack).
So it may or may not be 'one of the loudest Macs at idle' but I don't care.
I'm sorry if anyones Mac Studio has coil whine but I'm quite sure it's not universal, there are enough people posting in this thread to demonstrate that.
I think that I heard that the Ultra doesn't have this problem, maybe because of the different heat sink.