With a hot horse everyone can see the tension. With a lazy horse it hides, because it shows up as less movement instead of more. A horse that holds tension in his body closes the front door: the shoulder tightens, the front legs stop reaching, and everything you send forward from behind gets stuck halfway. Kicking harder adds pressure to a body that is already braced against it. That is why every stronger aid bought you a duller horse.
We do not chase energy. We release the tension that is blocking it. First on the ground, with patterns that teach him to let go of the brace and open up his front. Then in the saddle, where the same patterns translate into a shoulder that reaches, front legs he is aware of, and a horse that carries you forward because he finally can.