I have found the fodmap diet to be extremely helpful in reducing my IBS symptoms, along with finding my food triggers (for example, I am lactose intolerant & am finding I have allergies to certain herbs.) Just a blanket eat/don't eat 'veggies/fruit/grains/' etc hasn't been particularly helpful because some (like carrots or grapes) are perfectly fine for me, while others (like onions or apples) leave me in pain/brain fog/horrible poops. Even the ripeness level can change a food from safe to unsafe. I don't have a lot of budget, so I use online resources, but the Monash University App is the main resource people use and it is fairly inexpensive and the only accurate source, outside of this spreadsheet I found on a fodmap subreddit:
https://docs.google.com/spreadsheets/d/1aDeHiIYbPdd355BBQrxr7rz7xPIc0KEKQw-ADFQ6wUc/
I have found added relief from other dietary changes as well, such as incorporating certain fermented foods (like ginger & carrots) in my diet and avoiding nightshades as well. Also, being mindful of the times I am eating. I cannot eat within the 3 hours before bed without pain in the morning either. I have definitely had to re-learn how to cook, which has been mostly good for me as it involves a lot more fresh & nutritious ingredients & less processed foods.
