Just for starters the formula is not right. When we take the same simplifications that all the energy there is(maybe if we say at the end of the punch the other types of energy don’t play major role), is kinetic energy really simplified it must look like:

E(kin)= SUM of all components(i)(0.5* V²_i * m_i +0.5 * FI²_i * J_i)

Where V_i is the velocity of each component, Fi the rotational speed, m the mass and J the inertia.
Then the Power will look something like:
dE/dt = P = SUM of all components(i)(V_i * (V_i)′ + Fi_i * (Fi_i)′ * J_i)
where for simplification J_i is constant, V_i is the rate of change of the acceleration and Fi_i is the rate of change of the angular acceleration. Now maybe its just by me but at the end of the punch i don’t accelerate much more so the power is way down... So you are left with the maximum kinetic energy and IMPULSE. So in boxing we try to get maximum impulse on impact. For example in the right hand you try to get maximal rotational speed of your body and you don’t try to push of the punch with your right leg and hands.
Now if we go back at the beginning we will see that before the kinetic energy there was the potential one. Here you must ask yourself how do I convert the one type into the other in the most effective way (balance, form...). Other important aspect of the punch is the impact. How do you land your punch without loosing energy(for example distance). Other simple question is can I land it on someone in my life?
Now there is the other aspect. If you are a keyboard warrior, like myself, even a walk in the park will improve everything