The function of the Heart of God was simple. The ancient civilization had created it to be the universe's final safety protocol: right before the power of annihilation destroyed every order in the world, the Heart of God would activate and restart the entire world.
However, to realize that simple function, they had to put in an inordinate amount of effort.
To reset the world, even when using rough unrefined technology, still required a high level of understanding and control of the laws of the universe. They needed to be able to interfere with base universal data, and most importantly, possess a terrifying computational ability.
Most of the Heart of God's modules were dedicated computation units, and the rest of its modules were used to realize the interference of the base universal laws and the connection ports to the various other equipment.