Q: Purchased a cpo Camry 2016 se special edition from a Toyota dealer. My car while driving just locked its brakes and I crashed

There are a number of things that may have caused this, but unfortunately this will require an inspection by a professional to determine what may have caused this. I would suggest taking the vehicle back to the dealer to have them inspect the car. The most common cause for a hard to press brake pedal is simply not enough vacuum. Any brake booster requires a minimum of 18” vacuum to operate efficiently. Anything less than that will contribute to the pedal being harder to push. This can happen for a number of reasons. This can be caused by an incorrect hose that does not resist expansion being used on the line going to the brake booster. There is also something called a booster check valve that could be defective causing the air to travel straight through it rather than trapping it as it is designed to do. The brake booster itself may be failing which can also happen for many reasons.