For people who accept autism as a valid reason for not having your life perfectly in order, an official diagnosis won’t change anything.
For people who don’t accept it as a valid reason, an official diagnosis won’t change anything either.
I’m undiagnosed myself, and I’m not even seeking a diagnosis because it wouldn’t change anything for me. A piece of paper confirming that I’ve been dealt a bad hand doesn’t make me feel any better. The cards are already on the table - I can see them with my own eyes.