Before iOS 14 my iPhone was perfect. I never charge it when I sleep and it barely drops. But after downloading ios 14 the whole phone starts acting weird. My battery health is 91% but when the percentage is 15%, the screen will start to lag as I’m swiping between different pages. Then the phone would suddenly shutdown with atleast 10% left. I don’t know if it’s a hardware issue or an software issue. Does anyone know what to do?