I’ll put this differently so maybe my position comes through more clearly.

There are two biological sexes, and not everyone fits neatly into either. If you’re trying to make more categories, each will have a ton of exceptions and you will never have enough categories to cover the case of every human who ever lived or will live.

Analogy: there’s an island where there are 2 cities. There’s also a hermit living in a trailer up the hills, an airline pilot who travels much for work and occasional stays in one or the other city, and a cowboy who is on the run from the authorities so he never enters a city and camps in the wilderness instead. On this island, there are 2 cities and 3 people who don’t live in either. It would be absurd to say that there are 5 cities on this island.

But why is it more useful to call every imaginable developmental anomaly a separate sex? If we do that, does sex even mean anything? Definitions are as good as useful the resulting categories are. If you can’t even begin listing the biological sexes that you think we have to consider, what on earth will anyone ever be able to use those categories for? Yes, saying there are males and females is useful categorization of not just humans but many animals, because it captures a pretty significant dimension of individual variability arising from separate developmental programs. The existence of exceptions doesn’t render it useless, you can say “I have male chromosomes but my body developed like a female would “ without requiring a biological sex category covering your specific case.

Edit: btw this is not the area of genetics and Y is a chromosome not a gene.