I eat well cooked veggies everyday, even kale, collard greens etc. With fibrous greens, I remove the thick stem, keep the leaves and cook them until very soft. I have no problems with them. We need to invent our own recipes.
The only time I had issues with fiber was when I ate 10-12 large dates without chewing them very well. I had my takedown in March, so I didn’t know better...