I've been reading a lot about gut bacteria and fiber. They say our microbiota is a reflection of what we eat. Many of us, when first trying lots of fiber, don't have the colonies of bacteria best suited to deal with it, hence upsets like gas, bloating, diarrhea. Maybe it would be helpful for you to look into establishing a micro biota that feeds on fiber. Take a look online to read about this connection to gut bacteria populations and digestion, if it's a fix for your problem...it's free and safe!
I personally use 100% pure psyllium husks. No flavors or additives. (BTW: The psyllium POWDER capsules are a nightmare: AVOID!)
I mix 2 TBSPs of psyllium husks with about 10 oz of water. If you can get it down immediately (before it starts to set up), I've found it is not unpleasant. (I can even do it in a restaurant at the table with no one noticing). I've had my pouch since 1980. (resulting from acute bout of UC). I eat a very high fiber diet. Vegetarian and loaded with fruits and nuts as snacks. I have no issues. I take no medications, I have never had pouchitis and I never get up at night or have accidents. I know everyone is different and my story may have no usefulness to others, but if there is one person that can benefit, that's enough.
Best of luck to you finding something that works to make life easier.