Why is 1.8m optimal?
Your hifi is almost certainly plugged into a 15A circuit (I’m using US electrical codes here; adjust as appropriate for other countries). That means 10-20m of 14AWG solid core copper cable
from your breaker panel to the outlet into which your “audiophile” power cord is plugged.
Can you explain why 1.8m of “audiophile” power cable, tacked onto the end of a 20m run of “ripcord” (to use your derogatory term) is “optimal”? Why not shorter? Or longer?