Here are a few technical references to cable materials and constructions. I haven’t read them in a while. I’m just pulling them from my list of references that I put together a few years ago. I am looking for one that details the microcapacitor nature of copper and silver and how it differentially retards different frequencies. No luck so far.
http://boson.physics.sc.edu/~kunchur/papers/Audibility-of-cable-pathways--Kunchur.pdf
https://www.qed.co.uk/qed-genesis-report