Kiwi, flax, chia, prunes. Honey might help. Cooking with healthy oils like avocado or olive oil. Avoid apples. does she drink formula? Is the poop green? If so it could be too much iron. Miralax won’t help if she isn’t drinking a ton of water since it’s an osmotic laxative. Maybe tummy massages? You could ask dr abt probiotics and prebiotics. Try not to change too much at once tho it could make her super gassy.
Get her to blow bubbles/a balloon when she's on the potty, or even just pretend. This should ease the release.
Perhaps she needs more liquids intake ? More fruits and veg? Is there something she could be eating that is causing them to firm up that much? Poor girl
You can try daily probiotics for a month. Also chia seeds can help the stool consistency.