Even if I've failed to convince you, thanks for actually trying to understand, unlike most in this thread. The best link I can provide for further reading is probably this peer-reviewed article published by a biologist, Why There Are Exactly Two Sexes. Here's a few quotes:

Across anisogamous species, the existence of two—and only two—sexes has been a settled matter in modern biology

Here I synthesize evolutionary and developmental evidence to demonstrate that sex is binary (i.e., there are only two sexes) in all anisogamous species and that males and females are defined universally by the type of gamete they have the biological function to produce—not by karyotypes, secondary sexual characteristics, or other correlates.

This commentary advances a simple claim with broad consequences: In anisogamous organisms, the sexes—male and female—are functional classes defined by the type of gamete an individual has the biological function to produce (Bogardus, 2025). Males have the biological function to produce sperm; females have the biological function to produce ova (Parker et al., 1972). That definition is universal across all anisogamous taxa

As I've said elsewhere in the thread, nothing I've said here is actually a claim that I myself am making. I'm simply stating what the consensus is. Trying to find flaws in that definition is how science works, and it's healthy to poke at it.