An ADHD brain literally cannot form habits. Habits are not routines. Habits become instinctual. For example to brush your teeth you just “don’t even think about it.” With ADHD, everything has to be thought about beforehand to initate action, even if you’ve brushed your teeth 25,550 times before. It never feels easier. If sensory issues cause brushing your teeth to “feel weird” then it’s even harder to motivate yourself to complete the task. Yes, for something so simple. It is always the simple things.
You can be neurodivergent with both ADHD and Autism. Both of them are expressed on a spectrum. Variability if you will. You can also have Autism without ADHD, which means Executive Function is not impaired.