Well here’s an objective reality, there are hundreds of thousands of people who are trans gender. You can call them something else, but they still exist.
I could also say black people don’t exist, because race is a social construct.
I could say Asian people don’t exist because race doesn’t exist.
Perhaps children don’t exist, it’s just an identity, and they’re just young humans. Being an adult doesn’t exist, they’re just human beings. I guess I’m not an adult then.
They’re have been scientific studies on the brains of trans people that show trans person’s brains often resemble the gender they are identifying with rather than the sexual organs they were born with.
https://health.clevelandclinic.org/research-on-the-transgender-brain-what-you-should-know/amp/

It’s a scientific phenomenon that actually happens based in reality as a biological phenomenon.
People can call them any name, but they are still real. Trans people have been recorded throughout history, and many cultures actually recognized they exist and had places for them. It’s kind of like being born color blind, or with an extra finger, or with red hair, it’s rare but it happens and it has a basis in physical reality it’s more than just an identity.