If in the last sentence you would replace sex with gender than i would agree.

I think it’s more appropriate so compare race to gender because both are social constructs (that doesn’t make them less real. It just means the implications of it are not fixed changing over time and are depending on the society)

The historical race concepts tell that differences are genetic and biological. But they are wrong. To cite Wikipedia:

Today, the scientific consensus is that genetics does not explain differences in IQ test performance between groups, and that observed differences are environmental in origin.

Instead about the sex you are right. It is proven to make biological differences. And I find it often difficult to decipher which of them are based on sex and which on gender