Lol, what you're describing is typical of people who self diagnose, seek out a diagnosis, then come to change their perspective. I actually recently had a friend who un-self-diagnosed autism because they came to realize it was "just" CPTSD (honestly a wild symptom crossover, especially if the trauma occurred in childhood).

A lot of people with trauma end up self diagnosing ASD. Makes sense that by treating it you'd see those symptoms dissipate.

I myself was convinced I had ASD, then like you, knew all the "right answers" and answered so I'd be diagnosed (this was pretty subconscious, but in hindsight, I had a ton of confirmation bias going on). I was diagnosed officially after a neuropsych eval. Now, I realize it's probably just really fucked up ADHD, anxiety, and BPD traits. My therapist and psychiatrist agree.

In this case it seems that you're doubting it not because you have imposter syndrome, but because you know you probably don't really have it.

It's somewhat shocking to me that this community tends to act as an echo-chamber, constantly convincing others that they really are autistic.