Some speakers and amps are much more affected by the impedance and resistance of the speaker cable.
I also suspect that you have "golden ears" honed from many years of acute listening.
I could not hear analog cable changes with my last system, the Dynaco speaks and Dynaco S.S. amp.
I tested with 28 gauge twisted pair vs. Monster cables vs. 12 Gauge zip cord. Never dug into the esoteric stuff.
Also tried using heliax, a 50 Ω high power/high-frquency solid-line radio tower cable once, and couldn't hear it.
But your ears aren't mine and vice-versa (Moke breathes sigh of relief at not having 60 year-old creased earlobes)
Part of the fun of playback systems is the experimenting, the owning, and the knowledge that you toiled and fussed
to "get it just the way you like it."
One of these rainy Saturday afternoons, I'll have to go to an esoteric audio sales house and A/B top-end cables, just for hoots.