I can feel the "prove it" army coming. Seriously, glad you are getting more enjoyment from a great set.
OK. I respond, after all it is KZ thread
Surely, balanced is different so much more than cables, since for the most cases two amplifier chips are used, and in many cases - two different DAC chips. Hence the balanced is effectively a different source that is in the most cases a better one - easier to make cleaner, more spacious, etc.
Also good old KZ stock cables have resistance of 0.8-1.1 Ohm, so with many sources, the difference with a good cable (below ~0.3-0.4 Ohm) can be noticeable.
As for other differences, for instance of the copper and plated, - if one checks out of curiosity whether their "pure copper" cables actually plated and then cased in the copper-coloured insulation - the findings may be surprising
Then it is really hard not to chuckle for "the copper makes warmer"
Collecting my share of cables, my definitive conclusion is that the differences of the cables is all boiled to the source limitations.
After all, an ideal source will power any load to the same power identically. This ideal case is definitely quite far from the reality with the compact portable sources, and there comes the cable difference highlighting the source imperfections.
But why then actually not to go to the proverbial source?
Portable DACs are plenty and fairly affordable, just the price of few decent cables (or even less than some exhorbitantly priced ones), and the difference there is so much more real and striking!
Actually, it is so overwhelming for me - I am not sure what to do...
So my limited best advice - before investing in a collection of IEM (and cables, other than for comfort and aesthetics), make sure that you have few different sources - at least along the lines of warm/musical, cold/analytical, the difference and synergies can be huge!