sadly most of the consumer level switches and routers too for that matter are built to such a low price point that emitted interference is not a priority to reduce, even the power supplies are cheap as chips MIC SMPS for a $ a pop.
Most home systems perhaps dont have the chops to pick up some of this noise, and people dont hear it also as the systems can’t produce it well enough to be a concern.
I’m suffering electrical noise now in the 5.333KHz region and trying to track it down but its seems to be riding the mains wiring as far as I have been able to tell.