I don't share a similar identity, journey, or struggles as a he/they Tik-Tok demi-boy who isn't medically transitioning or doing anything to "transition" beyond choosing new pronouns and changing his name to Dylan.

Why not? Aren't they both advocating for biological sex being secondary to "gender identity"? I'd say that is a major point of agreement one could organize around.

But probably OP is aware that his "trans movement" is a men's rights movement. His public performance of a fetish has little to do with a girl following a trend or thinking she can only escape gender norms imposed on women by pretending to be a man.