Camp Damascus by Chuck Tingle. I was expecting a trashy slasher with some queer elements and an autistic protagonist, what I got was a good supernatural thriller with some queer elements and a very believable autistic protagonist - I would genuinely recommend it.
The writing is the weakest part, it feels very kind of pedestrian, like "here's some words explaining what's happening" rather than being artistic or beautiful or evocative but it's good enough for the story and characters to come through, and they're great. So remove the writing quality from the equation and it could be absolutely excellent