I bet many MTF troons have travelled down a similar path to Lucas; having few friends when they're young. Seen as weirdos. Bullied and mocked at school. In later life they reinvent themselves, troon out, but by then the narcissism and vindictiveness is too ingrained in them, like the troon equivalent of an incel that's eaten up by misogyny.
If they can get some attention online as some kind of "activist" or "trans icon", they get a brief dopamine hit and their ego inflates, but none of it is really real - which even they know deep down - and in those circles, you put one foot wrong and the majority of your supposed "friends" will throw you under the bus in no time.
Depression can be a bitch, with no rhyme nor reason to it sometimes, but Lucas knows he will never be a woman. He probably dislikes some/all of the few IRL friends he has, cos he feels he deserves better. He's got no career, nor achievements to speak of. He probably has family members that think he's a nutter. When he looks in the mirror, he can never think "damn, I look good!", no matter how much effort he puts in, which is probably why he puts in none. But when he hops online, he can project whatever persona he wants to project, and when he gets some likes/shares/comments, for a moment he's distracted just enough to feel OK. It's all desperately sad.