Why is my Iphone getting so hot?

My iphone 12, I have been using it for a year and a half and the battery is at 95% health. Whenever i use an app, my phone gets really hot and the battery drains way too fast. Note that these happened after i updated my ios to ios 16.1. I have factory reset and also reset the all settings and did not import any data from backup but the issue still remains. I am not sure if my hardware has any defect or its a software issue which apple needs to fix. I wish i hadn't upgraded to ios 16.