ios 16.6 battery draining & iPhone suddenly turns off or restart

My phone is iPhone 12 Pro ( ios 16.6 )(Battery health is 96 percent ), every two or three days it suddenly turns off or restarts, and after turning on the battery charge, it suddenly draining & decreases and shows 10%. And after turning it off and on again, the battery percentage returns to the previous state. I used several methods that I read on the web, such as completely draining the battery..., but none of them solved the problem. The battery of the phone normally works up to two days. Thank you for your guidance