Battery draining much faster since iOS 26

give it about a week before judging. after a big update the phone re-indexes photos, search and a bunch of other stuff in the background and the battery takes a hit while that runs, especially overnight on charge. if it's still bad after that, check Settings > Battery and see which app is at the top, sometimes one app misbehaves on the new version until it gets an update. turning off background app refresh for apps that don't need it helps too.