This actually might be the problem. When I first read through the comments, I dismissed ground loop as the issue but on second read, this is the wrong way to test.

A Ground loop can occur due to the two devices being on the same circuit. By plugging in to the same power strip you have made sure they are on the same circuit. You test for ground loop by making sure both devices are on different circuits and checking if the noise goes away. note, that different circuits is not the same thing as different outlets. usually all the outlets in a room (and sometimes adjacent rooms) are on the same circuit.

But you have a very easy test since you are on a laptop. Unplug it and run on battery. Does the noise go away? Then it’s a ground loop issue. You need one of these:

Ground Loop Noise Isolator for Car Audio/Home Stereo System with 3.5mm Audio Cable (Grey) https://a.co/d/gjElz7M