@lorenzomcgoo Switch to Begin Health fiber and HMO powder. Miralax is not a clean option for kids, tastes terrible and is not best for the gut microbiome.
Also, she might still not be getting enough liquids. Whole milk is ok, but avoid juices as long as possible, even watered down.
Consider testing her stool to learn about any underlying issues for this constipation. We've used Tiny Health extensively. They provide excellent advice that is largely food-based on how to improve the gut and constipation, as well as some allergies.
A probiotic might be in order. See above and check with the ped before doing so. We use Jarro and Pediatric Seed for our guy who suffered from constipation a lot.
Lastly, she might not be getting enough electrolytes. Bananas (high in potassium, have some mangesium) are a safe option for kids before getting into the liquid, colored options. Add a touch of celtic salt to meal a day as well.