One thing I find very off-putting, is the rose-coloured, almost "success guaranteed"-like image your website and app store page sketches.
This product is no wishing-well that your customerpatients can simply throw money at and magically feel better. For this to ever have any meaningful and lasting effect, they will have to put in some serious effort. This requirement should be very clearly communicated I feel.
Long-term dedication and commitment to a plan with uncertain results is not exactly what ADHD brains are known to excel at ;)
Edit: I also share the others' thoughts about your billing model not being very ADHD-friendly.
All-in-all, considering your listed expertise in this field, this is very concerning and not a good look at all.