Are you looking for a trainer? Or a veterinary behaviorist to prescribe meds?
If the former, there's a great list here:
https://yourdogsfriend.org/we-recommend/positive-trainers/
If the latter, I concur with the Dr. Pike recommendation. You will have to wait 3 months and the initial intake is costly ($195 for the mandatory behavior counseling session on the phone and another $500 for the medical consult with Dr. Pike), though my pet insurance paid for most of it.