I have the iPhone 11 Pro Max and the same issue is happening to me. I leave my phone fully charged before I got to bed and wake up less than 8hrs later to find it at 20%.
CCV_1022
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution