Below is a list of reputable (my current perception) consultants or resources from whom to seek guidance in challenging medical situations toward the initial issuance of a First Class Medical. If you are aware of any additional valuable entities (particularly if you have personally had a positive & successful experience with them), I’d be grateful for you sharing them here - thanks a lot!

Dr. Bruce Chien (aeromedicaldoc.com)
Pilot Medical Solutions (leftseat.com)
Aviation Medicine Advisory Service (aviationmedicine.com)