I usually long press the power button and when the menu pops up long press the red power off button. It should turn green and say safe mode. Tap on it and the phone should restart in safe mode.
Clear the camera app cache files Open settings /apps /and scroll down to the camera app Tap on it and a menu will open.. Look for an item on the list titled storage. Tap on storage and the options for clearing the cache and data should be there. Considering the issues freezing and overheating I would clear the cache and data.