OP, I don’t mean this unkindly, and I am autistic myself, although less severely affected, but your posts are all heavily slanted towards what you can’t do, and endless reasons for that, rather than any positive thoughts about what you can do.
As my DD often says to me, “Don’t bring me problems, bring me solutions!”
Try looking at this the other way round. Imagine there was no benefit system, and you HAD to work, or your children would starve. What would you do?
Start considering the strengths we have as autistics - the ability to focus intently on a single task, our attention to detail, our logical reasoning, our ability to cut through bullshit, to work alone and unsupported.
Think about what things you enjoy doing - could any of them be a potential earner.
It is all too easy as an autistic to get into a negative rumination spiral - to keep rehearsing in your mind all the reasons why you can’t do something. Cognitive behaviour therapy could help you break out of that, and I urge you to consider it.