I've seen recipes where people blend the veggies into a sauce and put it over pasta, maybe try that?
I worked with a dietician to help with this issue. It would be helpful to start tracking her food and bowels- that’s apps for this. Also try to avoid as much as you can anything that comes in a box or can. Is dairy an issue? If so you can try lactose free milk, A2 milk or some of the non dairy options. Increase her water intake and get a stool for her feet if she’s sitting on an adult sized toilet. I used a chart to “eat the rainbow” with every day trying to eat as many colors as possible. We got a treat at the end of the week if most of them were eaten.
We do smoothies with fruits and veggies and nuts in them, no dairy.
Same boat.. not sure if you do prunes, we call them frozen treat \ fruit and freeze whole ones then cut into pieces. When she eats them semi regularly it does help her.