Teach the dog not to bite. Most people don’t need a guard dog, they want a family companion.
Don’t acquire a dog from a BYB. You don’t know what you’re getting. Buy a dog from a reputable breeder or your animal shelter.
Most people who get a large powerful dog of any breed from an animal shelter is living blind.
You can count on the fingers of your hand the number, out of the thousands of shelters in this country, who have the time, the expertise and the resources to train the animal killing instinct out of the worse breeds.
I know this from many years of first hand volunteer shelter experience.
A PB from the shelter. What could go wrong there. Geez do you even think before you write?