Autism

As someone living in a country with universal Healthcare, it was easy once I knew I may be on the spectrum:

I went to a psych, and told him I made a self test and here is the result. So, he did some more tests and I got my diagnosis.

Depending if you are from the US or a country with universal health care, your millage may vary

I did a lot of therapy and getting misdiagnosed with stuff in my teen years and none of it was helpful. Talk therapy and group therapy actually probably gave me more trauma and drugs for conditions I didn't have were pretty counter productive. I got a bi-polar diagnosis, did the whole lithium with blood monitoring thing, and hearing in my weekly group therapy the stories real bi polar people were telling was like that scene where Dave Chappelle goes to NA for weed. I'd never had a manic episode in my life. So I told that doctor I was just done and wasn't coming back to see him again and he was like "That's a bad decision, you're going to regret it." Spoiler: I did not regret it. Finally in my second year of college I had a professor on the spectrum who recognized what was going on with me and he recommended me to the University Mental Health services and gave them some info on me, and I got my diagnosis. It was actually a huge relief to finally understand what was going on, and knowing I am autistic gave me tools to better understand myself and my learning and socializing issues, but other than that, it hasn't made a huge difference. I generally need some small accommodations at work but nothing major, and if I have to work closely with other people in group settings I like to let them know in case I do or say something puzzling to the normies, but other than that, it's basically just nice to have an explanation, the knowledge to lean into my strengths and avoid my weaknesses, and stay out of overstimulation/highly social/meltdown causing situations.

That depends on where you live. In Germany afaik you can get diagnosed either by a specialist, but have to pay for it yourself, or at an autism centre, where it's hard to get a place, but you don't have to pay for it.

Keep in mind that if you don't think an official diagnosis will help you, it also isn't strictly necessary if you'd still like to consider yourself autistic. If it seems like autism is explaining the person you've been your whole life then you're almost certainly autistic!

Diagnosis is useful for getting disability benefits or certain accommodations but most of those accommodations are things you could get if you have other mental health conditions or neurodivergences that are less stigmatized in the workplace. Also once it is on your medical charts you may run into more issues with medical care. You want to be very careful about who you tell in the workplace because you'll likely get discriminated against and it really won't help in cases where you're likely getting discriminated against anyways (most workplace situations since most people discriminate against autistics). Yes I know discrimination based on disability is 'illegal' in most places but it is extremely hard to prove especially in certain parts of, say, the United States. Diagnosis would also get rid of the nagging thought of not being "really" autistic. It's up to you.