While I share your pessimism for cables making major differences, there are electrical properties from one cable to the next which can make a difference (like capacitance). With that said, almost NO manufacturer (besides BJC’s) will publish their specs so you have an idea of the differences so you avoid confirmation bias!
I’m glad to hear some on hear say they have heard ‘no difference’ which gives me hope, but the profound differences some claim just have never existed for me regardless of the brand or non-science based explanations of why one cable is SO much different from another.