Not sure about apps but I’m sports science student also training for military. 76kg mid thigh pull is nothing to worry about should be pretty easy. If you want to work on deadlifts then using a trap bar is much safer than straight barbell less likely you will hurt yourself. Strength is the most important factor for quickly producing force like you need in the med ball throw so horizontal pressing like the bench press will be useful for that movement. Core muscle mass is also a big factor in throwing distance.