I remember one saying that asexuals have the highest amount of people identifying as trans or non-binary

Two points.

One, if you've got a sexed body, but you only understand, intellectually, what people do with those sorts of things, it certainly might not cement as well that you're this sex, as it does for het/homo/bi, insofar as it is your sex, and your compulsion to use it, that creates an identity with regards to other sexed people.

Second, about trans. In the case of autogynephilia, roughly 10% of them identify as asexual. The reason, however, is that of this proportion, their sexuality is 100% wrapped up in the paraphilia, and nothing is left over for interest in other people. This is better called analloerotic. An-without. Allo-other. Without eroticism for others, not asexual. They have a sexuality, it's just very atypical.