In my case it was very useful. Since Covid-19, and fatherhood in general (I'm 45), I went thorough a series of burnouts, which were getting worse. The diagnosis gave me an answer to the question, "why can't I handle the pressure"? Being autistic, I tend to need good theoretical frameworks to make sense of my life. Thinks that I don't control or understand, are a source of anxiety. As a consequence, the diagnosis gave me the framework and helped me accept that my career path had do change.
Now, I still have the same problems as before, but now they don't blow out of proportion. When I don't feel well I tell myself, this is my autism, I need time alone, I need to recover, and thus I don't get the extra anxiety. Also, now I don't try to fight my limitations.
So, nothing changes, but everything changes a little bit.