The difference between this and, say, gender dysphoria (I want to type diaspora for some reason), is that this goes beyond... actually, there's a whole lot of co-morbidity here with depression and other depressive disorders. Arguably gender dysphoria is a particular form of schizotypal personality disorder, though I just want to stress that the treatment of this disorder never is to "correct the strange thoughts". Usually it's a matter of coping, forming better social relationships (there's a lot of social anxiety involved here, which... can't say anything relating to that and gender dysphoria; others would need to weigh in), and in extreme cases surgical operation. Again, I have no idea to what degree gender dysphoria and social anxiety relating to paranoia tie into each other and would need others to weigh in. Additionally, most schizotypals simply see themselves as nonconformist or eccentric.
I really have no idea how you came to that conclusion at all.
In general, a personality disorder is a disorder in a person's personality itself, basically a pattern of maladaptive behaviors, inner thoughts, beliefs, etc. Schizotypal personality disorder in particular is a disorder in which they have strange beliefs and have paranoia regarding other people. In particular, that people have negative thoughts about them. The social anxiety is basically fear that others don't like them, unlike most social anxiety which stems from a negative self-image.
Gender dysphoria, on the other hand, is mainly a discomfort with how other see you, or with your own body. By definition, it is nothing more than that. This
may lead to isolation, social anxiety, depression, etc, but these are
not core to it. There is no paranoia that other people have negative thoughts about them. Any social anxiety is due to not being seen how you want to be, not because you fear others don't like you.
People with GD have a strong tendency towards a negative self-image because of their gender identity, but people with STPD don't have a negative self-image at all.
The two couldn't possibly be further apart.
(Not to mention that personality disorders are mostly a matter of maladaptive behaviors and less due to biological factors, whereas trans identities have a very very strong biological basis)