What I can tell you as a transgender woman is that occasionally I will read trans woman characters written by cisgender authors. And I can pretty much always tell when the author is cis, even if the character is portrayed respectfully, because they get some details wrong or something. But I certainly don’t think that they shouldn’t be allowed to take a stab at it, and I actually appreciate any representation that isn’t egregiously harmful. And I certainly don’t think that only transgender women should be allowed to write transgender women because then it falls on me, and that’s rather tokenizing, isn’t it?
Also it seems like demanding that only #OwnVoices authors should be allowed to write certain characters is an excellent way to enforce a situation where most books are about cishet white people.
And no: you probably won’t get all of the specific details of someone else’s lived experience correct, in much the same way that most authors don’t get all of the specific details about how, say, nuclear reactors or space work. But so long as your character passes as realistically human and not a one-dimensional caricature of what you think that other types of people are like, then I think that that’s reasonable.
Also, sensitivity readers are a thing, and enhance all of the above actions! Paying a reader from the demographic you have written to go over your writing and give constructive feedback is a wonderful thing to do. It benefits both parties involved not only in the financial and craft-honing senses, but also in the exchange of ideas and learning about someone whose perspective and lived experience are different from yours.
ALL OF THIS!!!