Stripped mounting screws

Many years ago I installed my first gen Ring doorbell. One thing that occured was that in screwing in the 4 mounting screws for the bracket, 2 of the screw heads ripped right off. Are they even metal? They seemed more like very cheap plastic. They were almost flush with the bracket at that time. Since the purpose was to secure the mounting bracket, it wasn't a problem then. But as I may be removing/upgrading the doorbell in the future, what are the better methods to get these out?