People can believe both that the physical differences between sexes imply some social/psychological/cognitive differences, and that society has unfairly categorized people according to their sex.

One can be anti-sexist and believe in sex differences writ large at the same time.

One example of such differences: https://www.science.org/content/article/pregnancy-resculpts-...

It seems more sexist to assume that differences mean one sex is better or worse. Let's let the whole richness of reality come forward, and embrace it for what it is.