Well you are eating a pretty varied diet only three weeks out. At that point I was still living on peanut butter, yogurt and cheerios.
I was vegan when I got ulcerative colitis, went to vegetarian, and then after the colectomy I added back white fish and soft cooked poultry. I feel depleted when I'm not eating enough proteins - I can tell because I start craving sliced turkey.
Perhaps you would try an elimination diet. Basically that means go on a limited bland diet for a few days, and see if your symptoms are relieved. Then add back one food at a time and see what happens.
On your food list are a couple that I love & know give me gas. Lentils, avacado, and coffee. YMMV of course. Many people get gassy from wheat or eggs, even peanut butter. Broccoli and cabbage can be hard to eat, compared to steamed zucchini, yellow squash, carrots, butternut squash.
Even with the blandest diet I think j pouchers are more gassy than most. I was pretty happy when I was able to pass gas with my pants on and not be afraid of an accident...though I've had some overconfident mistakes.