Are you sensitive to black mold? If you are, you need to avoid all food that has added citric acid. It's derived from Asparigis Niger, which is in the black mold family. I'm allergic to natural citric acid, and I've heard several people say that they were initially diagnosed with Gerd or IBS when it was artificial or natural citric acid. Certain medications can also cause a reaction to anything with citrus in it.

I found that an eleimination diet (with a dietician preferred) helped me figure out what I should and should not eat. I didn't use a dietician becuase I react to meats and poultry and refused to try pork or other not kosher foods. Where I live, I could only fiet dieticians who knew nothing about vegan diets and how to get a balanced meal. Working with a dietician, really helps, as they can guide you through the elimination diet process. The problem with seeing a doctor to run a whole bunch of tests, is that tests aren't 100% accurate for skin or blood tests for food allergies.

Avoiding grains, cereal family, quinoa, buckwheat, rice for 6 months, can really help heal the gut I was told. That elimination diet, should help you find what you should not eat, which in turn could get rid of the IBS issues for the most part. Some people had to go on the FODMAPs diet to get relief from their symptoms. I was told I should go on this diet, if at all possible. I refused because my diet is so limited already. I wasn't sure I'd get a balanced meal in my case.
Best Wishes!

Going through similar situations. First I went to Gastroenterologist for repeat endoscopy and colonoscopy and followed recommended treatment process. Kept simple food diary breakfast lunch dinner and photographed mg plated meal. Noted any unusual reaction including delayed symptoms. Patterns of symptoms such as chronic constipation and diarrhea episodes what where when events, home, traveling, eating out and potlucks. What makes symptoms worse.What improves symptoms. Obtaining allergy testing. Considering seeking dietitian advise. Autoimmunes can possibly make symptoms worse momentarily. I keep my rheumatologist advised. Wish you the best. Be your own advocate as you know your body best.