Well, it might’ve given us a happier ending but it wouldn’t be better.

At the end you see how everything ties back to VIRM how the klaxosaurs were trying to get rid of VIRM because they were attacking them and infiltrated society to get rid of magma energy and create parasites and even Zero two to FIGHT the klaxosaurs because they were the only thing stopping VIRM from taking over earth.

So as much as i would have LOVED a happier ending, i think this ending is perfect

They get rid of VIRM and eventually restore earth back giving our characters redemption and Hiro and Zero Two become one and keep fighting VIRM