I don't think the term is helpful. It is lazy, subjective, skirts detailed impressions and omits objective explanations as to why paired components sound good. How to get synergy is like asking how do a get a nice system. Learning how to read product measurements and understand designs and what sound they yield I think is key.
I do not know about your cable experiment of course, but ime most cables are predictable in their sonic attributes across systems and are not difficult to match. People often have their favorites.
I do not know about your cable experiment of course, but ime most cables are predictable in their sonic attributes across systems and are not difficult to match. People often have their favorites.

