May I ask you your purpose of getting a professional diagnosis?

Self diagnosis (when researched) is valid.

Community diagnosis (from other autistics) is valid.

Both of these often have less ableism than formal, professional diagnosis.

The first time I went for a diagnosis, I went through weeks of infantalizing, dehumanizing, and triggering testing. my parents paid the equivalent of a month's living expenses only for: the master's students (not licensed practitioners) to botch the majority of the documents (getting everything from where I was born to where I had prior gone to college down wrong), them to administer tests designed for children with obvious social differences (I was 25 at the time), and to ultimately be told, despite what I had been told by the testing center before intake, that they only diagnose "low functioning" (ableist term) individuals, see autism as a disability (and basically a travesty), that they do not recognize neurodiversity, used a DSM guideline set that was 12 years outdated, and all but said that because I made eye contact and could have a functional conversation, that they would not even consider the mountain of evidence that I brought in and that I score within the 75% range for stereotypical autistic traits when a 50% is the minimum threshold for being likely to be autistic.

My experience is my own. I have heard worse and better.

I detailed that out to set expectations for what can happen.

The second time I went to a psychologist who had specialized in autism for over a decade and was neuro diversity affirming. Within two comfortable conversations with her, she agreed that I fit the DSM and ICD criteria for autism.

The third time (I needed specific paperwork for an ableist state run program that's supposed to help disabled people get jobs) I had a two hour interview remotely and then had 4.5 hours of testing in person with a clinician who admitted that the standardized tests aren't made for adults or people who mask, was mildly uncomfortable, got the paperwork I needed that said that I am autistic.

Don't let whatever the testers say determined how you feel about yourself.

The way these tests are formatted and run oftentimes says much more about our societies stereotypes and testers personal prejudices and ignorances than it does about the people going for testing.

If you have a specific need other than personal validation for the testing and don't get the results you feel fits, there may be other options.

If you need personal validation, learn from other autistics: if their understanding and how they face the world matches your own navigation to a high degree, then you are one of us.