I agree with fire moons. You obviously care for your son and want the best for him. I’m 44 now but at his age I would have felt pushed and judged every time you hinted at or mentioned getting a job and I would have felt more and more of a failure.
Growing up with ADHD is never being good enough, never able to “live up to your potential” and continually failing. By 22 I was a heroin addict and living on the streets. I know how fantastic it is that your son graduated (I didn’t manage to graduate and then tried again and still didn’t) but I would be really surprised if he feels that way. The people around him didn’t take 6 years. He probably feels like a failure even though you don’t see him that way.
If he didn’t have ADHD, not to mention the emotional issues on top, then maybe stronger action would be in order but he isn’t a typical lazy kid. Four months isn’t long. Maybe some basic rules for contributing to the house in terms of cleaning and such and a time frame for when he has to look for work. That way both of you can have some time with the issue of the table.