Steve Sailer had an interesting article about the autogynephilia to troon pipeline where he discusses some of the common traits he's observed among members of that pipeline:

The second and in some ways more socially important type is the male-only disorder of late-onset gender dysphoria. This is frequently (and perhaps always) related to a rather comic sex fetish called autogynephilia in which at puberty, a normally masculine boy begins dressing up in his mother’s lingerie and masturbating in front of the mirror, imagining himself as the beautiful girl he desires.

For reasons that I’ve never seen completely explained, those with the late-onset syndrome tend to be highly intelligent; ambitious in their stereotypically masculine careers (e.g., Tur insisted on being called “Chopper Bob”); fans of hard science fiction (with Robert Heinlein a favorite); and, often, not very nice. They tend to be highly insistent that others validate their sex fantasy about themselves and relentless trouble to those who won’t.

Thinking about that second paragraph a bit and the sort of "autists" who end up trooning (eg. programmers, pro video game players and speedrunners), there does seem to be some overlap in traits, with the possible exception of the "stereotypical masculinity" (though those fields still seem to be hyper-competitive).

I think u/ernsithe has it right. They're two distinct pipelines that have a small amount of coincidental overlap. Autists are easy to groom because they know something is off. That gives troomers an easy opening to convince them that trooning out is the answer to all their problems. The autogynephiles are just sexual deviants who won't keep their fetish in the bedroom.