Is she screaming on the thicker formula/laxatives? If not then the watery stools any day as she's clearly no longer in pain. They'll get better over time but don't think its a good idea keeping her on normal formula if it's causing her that much pain and distress
Have you tried a more sensitive formula? Like kendamil goat milk or Bobbie gentle formula?
I'd rather watery stools than the baby screaming in pain personally unless someone can suggest a better solution x