Sorry my computer is up in smokes and wont get a new one for a while and idk if u play using a gamepad, but on the gamepad u can push L3 and it will auto target w/e it is that you have selected, and no matter where u go it automatically re adjusts your camera so u are facing that enemy.

For PC controls idk what it would be, i know for gamepad it is L3 so i would say go into keymapping or w/e its called, and find something that says "lock" "auto lock" maybe? or maybe switch to a controller mode and see if they have a re mapping available for a controller and just see what the action is called that is on the L3 button than switch back to keyboard and find that and put it to a hot key? maybe that will work?