Get screened for whatever you think you've got. Think you've got ADHD? Go get an ADHD screening. Autism? It's not easy to find a psych who does adult Autism screenings, but they're out there. OCD? You get the idea.
Regardless of whether the conclusion is "yes you have x" or "no you don't have x" the diagnosis will be accompanied by a detailed analysis of your psychological condition. Whether or not you are diagnosed, that analysis will cover the issues that led you to believe you may have that condition.
> It's not easy to find a psych who does adult Autism screenings, but they're out there
And it’s very expensive to get the diagnosis, it can be up to $20k in California
I think you mean the full diagnostic process? Screening is just the first step in (what should be) a long process to decide whether the full workup makes sense. Screening takes on the order of minutes to an hour and it doesn't come with a diagnosis, the actual diagnostic process should take many hours and several appointments.
This approach might help some, but it might hinder too.
There is a post here about someone who was misdiagnosed and bipolar and that later came up when security clearance was needed for a job.
And then what?
Nobody will accommodates you.
Suing for ADA violations will cost $20k just for a retainer. And then it's a gamble if you win or not.
And the US government wants to aggregate us into a list for who knows what reason.