Iphone 6s plus restarting continuously when we open any existing App

Hi,

My IPhone is getting restarted every time when I open an existing app like Whatsapp,Youtube,Facebook etc. Based on the suggestions read from Internet have done all the basic checkups like Updates,Storage and Network settings rest etc. Still the issue not resolved.

Currently IOS version in my IPhone is 14.1

Please help on this issue.