So then you grow up as autistic and/or ADHD person which creates a lot of social friction and conflict in your life, you're called lazy, careless, difficult, overly sensitive, and this is particularly bad if you're undiagnosed. You don't fit in socially so you develop social anxiety (this is par for the course), and after a while that can spiral into depression or even a personality disorder, you might start to self-medicate which can turn into a substance use disorder, and ultimately people afflicted by these disorders are taking their own lives at alarming rates. You should look up statistics for suicidal ideation among children and adults with autism for a reality check.
Most of this can be prevented if those affected were diagnosed and offered support as early in life as possible.
So no, having ADHD and autism, two very closely related neurodiversities, and then developing anxiety as a result of that is not at all unusual.
If there’s a phrase to describe this wonderful experience of life, it’s “social friction.”