I’m a historian. Being “trans” was unknown until the twentieth century, and in the early twentieth century (and before), a wish to be the opposite sex was understood as evidence of homosexuality, not “gender identity” (the concept of which also didn’t exist). I’ve written about this in more detail upthread.
Sexuality has been variously understood as linked to sex or not, depending on the historical period. A very small minority of same-sex attracted men sometimes crossdressed, for example in the “Molly houses” (gay brothels) of eighteenth-century London. But most same-sex attracted men did not crossdress, and were not thought of as necessarily “feminine” before the late nineteenth century/early 20th century. (In fact, in the Classical world, being attracted to boys was often seen as evidence of a man’s extreme masculinity.)
Men expressing the wish to be women were vanishingly rare to nonexistent before the twentieth century. In contrast, girls and women quite often wrote about wishing to be boys/men: this was historically not remotely understood as a desire to actually be a man, but as a quite natural response to the restrictions on freedom and expression faced by women compared to men. In the early twentieth century, “inversion theory” claimed women who felt they were “really” men inside were actually lesbian.
The current concept of being “trans” came into being in the second half of the twentieth century with the term “transsexual”. This was initially largely applied to a very small subset of men. “Transgender” as an idea and a word started to take shape from the 1970s onwards: but a lot of men and women who people have recently re-categorised as “trans” never saw themselves in that way, but instead as gay or butch men/lesbians.
The current conception of “trans” actually has much in common with the “inversion theories” of the early twentieth century, which argued that same-sex attracted people were “inverts” who had been born the wrong sex: “the masculine heart beating in the female breast”, as Havelock Ellis put it. (However, don’t get too excited: Ellis was a rather repugnant eugenicist who thought poor people and the “lower” races were “mental deficients” who should be “bred out”: he also could only get sexually excited by listening to women urinate — he was a great early proponent of “kink”). Anyway, “inversion” theories were quickly abandoned as offensive by gay and lesbian people in the second half of the twentieth century. (Interesting that they’ve effectively been revived as “gender ideology”, though.)
If you want to claim “trans” people have always been around, you need to produce some actual historical evidence of this: and evidence that isn’t just evidence of homosexuality, crossdressing, or rhetoric (hint: when Elizabeth I says she “has the heart and stomach of a man”, that isn’t evidence of her actually being trans: she’s using a rhetorical trope to defend her queendom as just as good as a kingdom).
You will have a hard time finding anything from the pre-1900 past that actually fits the contemporary idea of “trans”, because people just didn’t view themselves or the world in that way. And the idea of “transition” simply didn’t plausibly exist before the first public availability of both antibiotics and synthesised hormones in the postwar period, because nobody could have any “sex change”/gender confirming” medical treatment until then.
You claim that trans is a natural condition with a “durable and heritable underpinning” (what on earth does that mean? How can it be heritable, by definition? And where’s the evidence?) The reality is that trans, far from being anything innate, is largely a social contagion produced by a whole range of different factors and fashions. A 4,000% increase cannot remotely be down to “increased visibility” and people feeling they can “come out”. It doesn’t make any plausible statistical sense whatsoever.