One of the gastros (my favorite) was a woman who methodically went step-by-step diagnosing, asking for tests, and giving preventative treatment (when applicable) for everything below the esophagus, she didn't suspect Crohn's at all.

Early on, crohn's was a hypothesis I had but I quickly moved on because there's very little evidence to support it in my case; and a colonoscopy isn't something I'd accept based on very little evidence.

The ENT told me "If you don't get better with the gastroenterologist, we can consider a septoplasty" but he was kinda skeptical that a deviated septum alone would cause this amount of phlegm.

Regarding allergies, the respiratory specialist rejected it. And over the course of these treatments, I self-prescribed Claritin (which didn't do anything), followed by Zyrtec (nothing either) to rule out allergies. Also, this is consistent, not seasonal, and not food-related, the latter which I have controlled for.