I have had this issue of gas, cramps and everything coming out looking the same as when it went in when I've gone backpacking. I make my own dehydrated vegetables. I have come to the conclusion through trial and error that raw vegetables combined with not enough water rehydrating them is the problem. Dehydrating cooked vegetables helps 90% and ensuring enough water to rehydrate solves the rest.
Why should you care? Perhaps more cooking or cooking more thoroughly and also drinking more water will help. I suspect cooking will help the most. So try veggies that taste best well-cooked and try roasted, caramelized, baked, mashed, added to soup or stew or other methods that break the fiber down a little better.
Female, 5'3", 50, Max squat: 202.5lbs. Max deadlift: 225 x 3.