These studies show that the measured effects are statistically significant; that doesn't mean it's universal, only that it's prevalent enough in the population to be detectable. It doesn't mean that this is *the* reason: only that it's part of the puzzle.
Loads of trans people have “always in some way felt like this” – and loads of trans people haven't particularly noticed anything for decades. Academic explanations are very much incomplete: many don't even know what they need to be explaining.