Oh boy! Very excited for this as I've had similar experiences with my ZMFs, ZMF HP cables as well as interconnects, and USB / power cables and have a similar conclusion; it's the whole chain.
In my case I live in downtown silicon valley in a condo 15 stories up - there's a butt-ton of EMI and dirty power - it wasn't until I replaced
*all* my cables with better cables that various buzz / hiss / other annoyances went away (I tested multiple versions of each one, one at a time). Those were my observations, and funny that some are invested in saying it's placebo or whatever ... either way, I don't care, it addressed my concerns.
BTW - my HP cable experience is that it seems to come down to architecture / build quality more than this copper or that silver, but then I've only tested 10 or so (and I have FAR from a summit-fi system).
Anyway, I'm pretty excited to hear your observations and politely accept them without a bunch of "
ACTually ..."