Again,there are a few problems going on.
First, transgenderism is a very new condition, historically.
Second, it emerged at a time of increasing secularization and scientific ability to do human experimentation.
Thirdly, there is no standard definition of the word “transgender”
Fourthly, because of social factors that go as far back as the sexual revolution and the presence of powerful lobby and pressure groups (make no mistake—in spite of all the boo-hooing transactivists do about their “oppression”, they have a great deal of power and influence), scientists hands are tied when they try to study it.
The Church doesn’t generally rule on particular medical or psychiatric conditions, but on the morality of various treatments.