I feel your pain-literally. If I stay away from fresh fruits and vegetables I am much better. Yeah, that limits a lot of delicious foods. Dairy can be an issue, that sort of comes and goes. I find almond milk works well.

Keeping a food Diary may help. And track reactions/ upsets even 24 hrs later

Could be good additives too

Food

My best friend and I both deal with crohns/colitis/IBS. Ever since she's cut out gluten, she's felt a lot better

Like you, I've tried "every" diet...I'm sure there's more out there but I can't think of any more to try. That said, I have been on the Specific Carbohydrate Diet (SCD) for 1.5 years, which my GI recommended it in conjunction with medication. This has been a game changer for me. The idea is that you're eating predigested foods that are absorbed in in the upper intestinal track, leaving no work for the lower part. The clinical trial on this diet say it can take 2 years to make a significant difference for Crohn's, but most people report feeling a lot more energy and comfort in the first week of being on the diet. I can't speak for it being a solution yet to Crohn's or anything, but I absolutely believe it to be a necessity during flares, trying to keep nutrients in, and wanting to reduce discomfort. I have not waivered on this diet, and while I do feel mild discount from time to time, it's much better than it was before for me. A bit of warning if you start this, there's a huge learning curve for this diet....and don't compromise by starting on the advanced part of the diet. Begin on the intro diet and get yourself an instapot with yogurt settings for the homemade yogurt you'll be making. It's so much easier and better quality than the yogurt makers out there and you'll be able to use it for other recipes.