I have also purchased moderately expensive cables, such as mid-level audio quest and DH labs stuff and compared it with no name, lamp cord and Amazon‘s best types of cables and noticed differences so small that they made me doubt my judgment as to whether they were doing anything at all.
Expensive does not always mean quality or a good match for your gear.
My local high-end store owner handed me a box with a half-dozen cables, all from reputable cable companies. All were expensive to wire up an entire system of separates. They were complete sets (enough to wire up my entire stereo with each brand -- so lots of cables in that box). I tried them all, and returned them all. They either did so little that I had to strain to hear it, and a couple of them made the sound worse.
At the time, I did not know one brand from another. To me, it was just a box of cables.
The store’s owner then handed me one more set of cables to try. And those were the ones that I purchased.
I asked him why he did not include them in the first box. He said that they were more expensive than the others. But when I demoed them, I neither knew the brand nor the price. I just heard what I heard, and made a purchase. They were expensive, but I did not know that when I fell in love with them.
The first round of cables that he lent me were all copper (if I remember correctly). The ones that I purchased were silver. That is what drove up the cost.

