I guess it can be a bit of a lottery from the sounds of it, same thing with OLED with banding etc.Many PS5s (maybe even most) have either fan noise (there are three different fans used, and some are noisier than others) or coil whine. Mine has the latter, and while it's not loud (it's not noticeable when a game is making noise) there's always a buzzing sound at all times (more or less so depending on what is being rendered). If I mute the game I can hear it from several meters away. My fan is very quiet, but not absolutely silent. No fan is.
If you got lucky and got one without any of these issues, congrats. But they are common issues, and I've read so many accounts of people sending their consoles to Sony only to get them back no different. Basically, Sony considers this (at least the coil whine) "normal", just like GPU manufacturers do.