Don't try to tell an "authentic" story. Instead, tell an "inauthentic" truth.
Critiques should not make you question the value of your work, or the value of yourself.
Let somebody else write only allistic characters. You can write a character who is probably, or maybe, on the spectrum, but this does not need a huge reveal or internal struggle—it can just be a thing you do, among other things you do, as an author.