I don’t think I have diagnosable ADHD, but I have noticed that gamification features like “streaks” often cause more problems in building habits than helping them. My daughter, who is diagnosed with severe ADHD, eventually had to “give up” some of the streak based apps like Duolingo because they are, imho, preying on our desire to complete “streaks” only to increase in-app activity for their own platform.
I’ve been really loving Llamalife - https://llamalife.co - they don’t do habits but they organize a lot of the schema around people who get overwhelmed easily.