My iPhone 12 Pro is draining the battery in half normal time

This phone is relatively new and not overused. Battery Health status is 100%, yet it drains by noon to 2pm every day now, with Safari and Outlook being the primary users daily. But it sits most of the time, not even being picked up. And even with all apps closed, it drains by early afternoon daily, with the back of the iPhone getting very warm. I've owned every version of iPhone since iPhone 4, and never seen this poor of battery performance. And it used to be up to 2 days of use and still 25% available, before iOS 14.5 was updated. I've read all the blogs and turned off most of the suggested items working in the background. Something is seriously draining the battery daily, and it isn't necessarily apparent why?