Hello. I'm an autist, or "on the spectrum" as people put it nowadays. Here's why I think there's such a link between autism, transing oneself, and suicide.
You're a teenager. You struggle with all these hormones blasting everything and how it makes your life unpredictable and difficult. Previously you found girls / boys (delete as appropriate) lame and stupid, but now, you want to have sex with them all of a sudden. And lots of it. Only there's a problem. Your autism makes it an impossible ask for that boy / girl you fancy the most to be attracted to you. All the other teenagers of your sex seem impossibly adept at negotiating it and talking to them while you find it like searching for a needle in a stack of needles.
You ask people for advice. Your teenage peers laugh at you for doing this or sneer or exclude you or all of the above. If you're a boy, they'll probably duff you up every so often just to make sure you know your place. If you're a girl they'll exclude you and spread rumours about you. Adults either are too busy, give well meaning but 20+ years out of date advice (life and youth culture was different when they were your age), or patronise you by saying that "it'll happen, you just need to have patience." It won't, incidentally. So you look online. After all, they don't know you. They don't know that you're an outcast and people in online spaces seem to get it. Then someone tells you "maybe you're trans and were born in the wrong body. That's why you can't seem to relate to the other girls / boys in a way they find acceptable or find a boy / girl who fancies you or you can attract." They shove all these leaflets and things at you.
(This process is known as hatching an egg. It makes me feel polluted that I know this.)
You read them. Of course! It all makes sense! You've always felt like something was wrong with you, this must be it! Result - you're taken up the Tavistock, filled full of puberty blockers and cross sex hormones, and rushed into surgery to have your fool / bits sawn off. I probably would have been pushed down this route.
And then you find out you've been sold a bill of goods, you're in constant pain from having your genitals mutilated, you still feel like and are an outcast, and if you raise this with your trans identified new found family and say that you maybe think you've been sold a bill of goods they'll turn on you.
At that point, the rope seems like an appealing option.
I don't think as a society we handle people with autism very well generally. Yes, it's better than when I was a teenager in the late 1990s and early 2000s inasmuch as they aren't written off as drama queens and basement dwellers but now instead "geek" stuff is colonised by normies larping as same because they watched The Big Bang Theory and turning those interests into another outgrowth of the very culture the autists sought to avoid, and people "on the spectrum" are headpatted and patronised and pushed to basically be vaguely out the way rather than actively hated and derided. What is needed is not to patronise autists or to hate them but to simply understand that's how they are and actually treat them as normal human beings, not a morality pet. Also stop enabling them to treat their autism as their entire personality.
I also suspect there's a lot of transing the gay away.