Hi OP, my ASD DS, who is early 20s, is bright but not a people person and quite distractible. He is easily made stressed and anxious.He would stay alone in his room 24 hours a day if he could.
He did a higher level diploma in computing at college which he scraped through with a lot of teacher support then said he did not want to have anything to do with that subject again.
We were referred to Mencap by our local authority (after I had stomped my feet a bit) and they have been fab. He has had a couple of unpaid job placements with very good support from Mencap at all times and has just been offered a paid job by one of those placements.
The job is kitchen porter in a large commercial kitchen. Not one I would ever have chosen for him or thought he would go for, but he loves it. The employer has a good team with strong working structures and they have a lot of fun working and they feed him, which he thinks is great. He works very part time but they have said if he wants more days at any point he can have them.
Yes he has the brains to do more, but he enjoys it, likes the fact he does not feel stressed doing it and is very proud he is earning money. That's good enough for me for now. Maybe he'll want to move on at some point, maybe he won't. I don't care, I'm just happy to see him happy.
The point of this rather rambling post is that sometimes, we think we know what will work, only to find that actually we don't.
Based on my experience I'd say start with your local council employment service for young people and push for a referral to someone like Mencap. The actual council service were useless so do push them.