Agreed on practicing maximal braking. If you get to the point that the rear wheel lifts AND you don't skid the front wheel or go over the handlebars, you can do no more. If you crash because you did skid the front wheel or went over the handlebars, then that pain you are feeling is irony, where you injure yourself developing skills that you need to prevent injuries. Swerving is also a valuable skill.

Just know that the act of braking transfers weight and traction to the front wheel, up to 100%, so that the front brake is very, very important to reduce stopping distance. Transfer your weight to the rear as you brake so that you can use that wheel to brake when it is on the ground, and so that you won't go over the bars if it isn't on the ground.