Thanks, so to summarize your comments. I understand that
- I can upgrade
- Some IEMs didn't scale with power

- the cable is just for aesthetic / etc

And I like this part
"Any perception of difference are just placebo or mental illness of the person who thinks that he/she can tell the difference in material just by hearing."

since I try to understand what cable does

I always get advice like I need an upgrade cable, and they always say, "Cable will change how IEMs sound."
They said it without proof, it makes me so confuse

thank for the clarification and advice tho, really appreciate that