The push to move away from gametes as the unifying definition of the sexes to collections of sex-related traits is as crazy as modern astronomy going back to the geocentric model of our solar system and adopting complex "epicycles" to explain aberrant patterns like planetary retrograde motion.

De-centering gametes in sex is like de-centering the Sun in our solar system. Sure, you can construct increasingly complex patchwork models that superficially appear to validate your preferred conclusion, but in science we abide by what's called the "principle of parsimony." This is a methodological principle that says that, when faced with multiple explanations for a phenomenon, one should favor the simplest one that requires the fewest assumptions and still adequately accounts for the evidence.

Just like every astronomical observation of our solar system suddenly makes elegant sense when you properly center the Sun when constructing models of our solar system, the patterns in reproductive biology across the natural world suddenly snap into place and make sense when you center gametes. That's because other traits like chromosomes, hormones, secondary sex characteristics, behaviors, etc, all orbit gametes.

Gametes are the center of mass in reproductive biology.