Battery should be fine, I mean yeah, deffect can happen but that doesn´t sound like an issue here. It depends on a lot of factors such as brightness, refresh rate, apps in the backround and how much things you have turned on. I´m spending most of my day on my phone, I charge it daily from 20% to 100% and It lasts whole day and by the end of the day I still have like 25% to 30% and I´m a really using the phone almost 9 to 10 hours a day. So as I said it depends on a lot of factors, try reducing the brightness by half, turn on dynamic refresh rate and keep off settings and features you don´t really use as much as you thought.
