Thousands of years? Please. Just because you’re ignorant of history and culture doesn’t mean you can make things up. Gender variance has been part of many cultures since time immemorial. The kathoey of Thailand, the hijra of India, the fa’afafine of Samoa, the berdache of Native Americans, among many other traditions. Hell, Greco-Roman society had the priesthood of Cybele which was comprised of castrated men who dressed and behaved as women, and the Roman emperor Elagabalus once offered the entire empire to any physician or magician who could make him a woman.
Moreover how much research have you done exactly? What about the neuroscientific evidence that trans people have brain structures like the gender they identify with? Emerging research suggests that trans people are the result of hormonal misfires from their mothers during their fetal development causing the brain and body to develop differently. There have been peer reviewed studies by credentialed neuroscientists, but I’m sure a person as steeped in mythological nonsense as you are doesn’t care about pesky facts and reality.