Still feeding every 3 hrs or so

I'm ebf and my girl is 5 months. The nights are still relentless for us. Part of it is she has bad reflux. I was thinking about feeding her a formula bottle (it wld have to be alimentum) before bed to see if she maybe sleeps longer and than pumping that feed. Anyone else in the same kind of situation? My first was like this too. He was 20 months before sleeping through the night. 😖.... Now he sleeps like a brick once his head hits the pillow!