"Since not mentioned above I use Inakustik Referenz Ethernet loom.
Handmade in Germany."
How can possibly wire cables be hand made? annealing/twisting/stranding/extrusion/cabling need different machineries and multiple manufacturing steps.
They probably import ethernet cables from China and snake oil them by hand.
Not only this German company but most of them buy/import and resell cables. So don't be fooled and waste money. Try Amazon/Ebay. Easy to return with Amazon!