I cannot make variations based only on colour!

I hope someone can help!!!

I have been trying to create a parent with 4 child variations for socks that I want to sell. Amazon people keep telling me to choose color as a variant. I do that, but the variations table does not show up! I must use a second variant (eg material, size)... but they are all the same material and size!!! If I add another variant, Amazon will give me errors in the pictures and list all the products under one picture! It doesn't make sense!

WHat's worse is I had such a variation made before, but I now have a brand, and I cannot use what was already created, Amazon says i have to create a new one! And so here I am!