Those have coil whine.

For anyone looking at getting an XPS, beware that this is a consistent problem. I notice it on my 9570 (2018), and I saw a review of this year's XPS 13 9380 (2019) mention the problem. Googling shows it has been a problem since at least the XPS 9530 (2013).

Yup. The damning thing is, when questioned about the issue, Dell representatives have always declared that the HW is working within specs.

I don't recall the exact wording, something like "noise emissions level is under some required threshold" (I don't have the link at hand but I think I can rescue at least one from Dell support forum). The thing is, to me the fan noise when it turns on is less annoying than the high pitched whine.

I have an old XPS 13 model (9333 I think, the battery is still going strong tho) and with the keyboard backlight turned off (I won't use it anyway) and no USB peripherals attached is dead silent. Otherwise, If I plug a mouse or an USB hub/network adapter there is the continuous whine.

To be honest, I can only hear it in silent rooms in my home with window closed, in an office environment it's droned out.

The whine is the only gripe I have with the HW as Debian has worked flawlessly with it.

They also fail in other ways at relatively high rates (trackpad, sound, display, ...)

And my XPS 13 9350 (2015) has display problems.

My screen stopped working for a week and started working again for absolutely no reason.

It's a known problem : https://www.dell.com/community/XPS/XPS-13-9350-Black-Screen/

And none of the mentioned fixes worked more than a day for me.

Can't speak to the newer ones, but people griped about my model (9343, 2015) having it as well.

Mine's quiet as a mouse.

Sample size 1, maybe I was just lucky. But happy people don't tend to be as loud as angry people.