I work and supervise OT’s.
They tend to work on fidgets, environmental supports, sensory stuff, organization, and self-regulation strategies.
A lot of the stuff that is good for ADHD overlaps across professions.
In a pure ADHD case, they don’t really offer much different that a good psychologist, ed therapist, or similar practitioner.
They can be pretty useful if there are other diagnoses.
So long as there are no social-emotional-issues they can be just as good as other professions.
If you get to choose, I would focus on the quality of the professional, not the letters after their name.