OP I haven't read the whole thread but I have read your posts.
I just wanted to come on as a Mum and as an educational psychologist to say, you aren't alone. I have a neice (28) and a son (25) who have very similar issues to those you describe. Both are very intelligent and knowledgeable people who just find life extremely difficult. Both are unable to work, though my niece has recently begun to volunteer a couple of hours a week which j am very proud of her for.
There are many people who don't understand how autism hypersensitivities, processing issues, executive functioning deficits and sever social anxieties can absolutely prevent a person from managing to work even though they theoretically could.
My son had a full breakdown when he tried university - his grandmother had thought he was bright enough for Oxbridge, but we tried a fault local uni. It nearly killed him. He spent 2 years under the covers in a dark bedroom. 6 years later and he now leaves the house alone to pop to a local shop and goes climbing with his career once a week. He is incredibly clever and totally unable to manage his life. He didn't eat or wash when he was left to his own devices. Heck, recently he was desperate to try D and D and I found a local group - he so wanted to go - and spent the 2 hours we stayed whimpering quietly and literally shaking while trying so hard to take part. People who think the only severe autism is the non verbal and learning disabilities type just don't get it, and never will.
Now from my pov I am incredibly proud of the young people in my life. They are not giving up. My niece has transformed her ability to manage since she had a social care assessment, she pays for a career twice a week who helps her with household tasks, shopping etc. My son is a few years younger but very close to his cousin and I live in hope that one day he will be able to manage like she does. Whether or not they ever manage paid work does not matter one iota, and neither should it to you, and it's nobody else's business. You get disability benefits because you are disabled. That doesn't mean you will never be able to work, who knows? Just keep on keeping on.
I have other autistic family members who find their comfort in working. Everyone is different.
When the autistic youngsters in my life wonder about their validity I like to quote Desiderata to them - "You are a child of the universe, no less than the trees and the stars: you have a right to be here".