Neurotypicals have difficulty with mindfulness; for folks with ADHD, it's extremely difficult. You have to sit still and do nothing for an extended period of time, which is a pretty heavy lift for somebody with an attention deficit. But it does help, yes.

One method that I've had success with is to work my way up. I do meditation for 1 minute; the next day 2, then 3, until I get to 20, and then I try to stay there. That's because the most important part is building the habit. Also, doing short sprints frequently is more effective than doing a marathon. 5 minutes a day for 12 days is better than 60 minutes in one day.