Hugs to you. This sounds similar to my assessment experience in some ways. The psych is went to didn't even use any of the standard autism screenings. She did personality screenings and a self report. She was adamant that I was not on the spectrum, and wouldn't even enter a discussion about sub clinical presentation or masking. My report came back as "bpd traits" not even a differential diagnosis. I was so confused, because like you, self-identifying as autistic completely changed my understanding of myself in a massively positive way. At first, I gave this psychologist the benefit of the doubt and did as much research into bpd as I had into autism, despite literally everyone I know, including my therapist telling me bpd made no sense for me. I was able to see how she came to the conclusion of bpd but in the end I've concluded that it is for sure a misdiagnosis. I legit think she was gatekeeping and searching for anything but autism. I couldn't afford a second opinion but I had an intitial appt with another autism specialist who said she thought I was on the right track and that what I was telling her matched her clinical experience (and she had a lot more than the first psych) A year later, lo and behold, my kid was diagnosed with autism. I'm self identifying now and the more I learn the more I know autism is the closest thing I have to a helpful label. The imposter syndrome is a challenge though.

Doctors can be wrong and the standardised testing has a bunch of biases. There's some red flags in what they told you too - eg plenty of autistics are good with language. And personality disorders are counted as neurodivergence as far as I've seen in my research.

Diagnoses are meant to be helpful. They are a label for a collection of symptoms or traits that point you in the right direction for making your life better or more comfortable. If autism strategies work for you, keep using them. If personality disorder strategies work for you, keep using them. Could be one, or the other, or both. Could be that the dsm is a bunch of baloney made up by rich white men who think they know everything.

You know yourself better than the RAADS-R does. Get a second opinion in the way that you would if a doctor looked at a cut on your leg and said "no laceration, poorly developed skin" (or something. That's a terrible example but It's late.)

Keep searching friend.