+1 Everything matters.
I’ve experienced huge improvements by building my own umbilicals. The last one I built was to connect the two units of the Aurender N30SA using sixteen 23awg pure silver solid core conductors. While not cost effective. the improvement in the dynamics, clarity and presence after break in was impressive. Aurender got in touch after the fact they acknowledged dissatisfaction with the basic UPOCC umbilical they were including with a $24K unit. For anyone interested, I documented it on What’s Best Forum. Here’s a direct link to the post:
https://www.whatsbestforum.com/threads/aurender-n30-to-stay-competitive-in-2021.32203/post-761694