How do I install safari so it can’t be deleted

Safari is not an app that can be deleted. See: Delete built-in Apple apps from the Home screen on your iOS 14 or iPadOS device or Apple Watch - Apple Support

The Safari app is not one of the apps that can be deleted but with iOS 14 it can be removed from the home screen. If you have iOS 14, go to the App Library (swipe left past your last home screen). From there you can touch and hold an app and slide it left back to the home screen.

Hackers and scammers CANNOT delete Safari, period, end of story. Safari is part of iOS and always has been. It cannot be deleted by the user or anyone else. It can only be hidden by the user.