13m toddler still relying on formula

hi mummies, my LO(13m) still wakes up thru the night for milk. We recently changed to toddlers formula but she seems extra fussy crying through the night and waking up even more. Dont know if we should go back to stage 2 if she is not ready. As context, she naps in IFC + sleeps from 7pm - 6am with milk breaks at 11, 2, and 4. We’ve tried extending her sleep time to 9-10pm but she still wakes up at the same timing. She eats breakfast, lunch, dinner.