Idle Battery Drain (iOS 17.4.1)

I am experiencing an idle battery drain issue in iOS 17.4.1. As you can see in the screenshot, from around 5:30 AM to 1:30 PM, there was no activity, but my battery went from 47-48% to 23-24%. I don’t understand why this is happening. Could it be because I haven't updated to the latest iOS version? Please advise me on what I should do.