My experience, now 51 months post colectomy:

7 months after surgery, I was having trouble with digestion - had to eat smaller meals/more frequently. I looked for things that were easy to digest. Had to push fluids even though I hated to because of the loose stools. Note: I was still doing chemo at the time, so it's hard to isolate the impact of the chemo vs. the recovery from surgery.

Metamucil or equivalent (as a slurry with minimal water) was helpful to tighten the runny stools, but wasn't helpful with any gastric pain/discomfort and may have worsened it (constipation) if I took too much. It had the side effect of severely foul-smelling flatulence, so I stopped it.

I've found some foods can cause such pain even now - I have difficulty with some, but not all fats - heavier, plant-based fats seem to be the worst for me. Lots of cheese and spicy things in excess cause issues too. And no more all-you-can-eat buffets! Very tight limits of chocolate as well (sorry).

I do have difficulty staying hydrated even now, so that's something to look into.

Hope that helps.

All the best.