It can be other things. Some of why I didn't get stuff done when younger was actually a symptom of PTSD from unrelated trauma. Basically my stress response is messed up and so anything I could link to stress or shame can make me avoidant, which snowballs into not doing the thing and more stress.

When I unlinked daily tasks from shame and stress I could suddenly do them, as I actually have ok executive functioning when PTSD isn't messing with me to cause avoidance which as I understand would not really be the case for ADHD. Although PTSD and the like can also pop up in ADHD people who were bullied for their symptoms.