"Another candidate would be the whole of nature since no part of nature could exploit the whole without undermining itself."

If you had just stick it out with this, then you would have opened the door, Benjamin. But that is not what you did.

Once you see it all; it is very easy.

First off, we only have data about the origin of matter.

Scientifically, we do NOT have any data on the beginning of energy, time, or space. So, melding all in one single event is definitively not scientific. That is where you are overstepping yourself, and some physicists may do the same.

Since energy does not get lost, we can start out with it. We do not need to explain where energy came from, because a scientist cannot do that. It is not available for anyone to explain where energy came from.

A scientist is not a priest, so we should not dabble in the religious or philosophical realm. We must stick to the scientific realm. And when we do then we can actually declare quite a bit (but not all).

The Big Bang event is about the materialization process of (some) energy into matter.

The whole of all original energy undermined itself, but in effect caused damage just on a segment of all original energy.

You see how close you got? You were almost there, and then you turned around and walked off.

We ourselves are part of the Milky Way galaxy. It is the largest maintained energized setting for us, though there are smaller settings, Solar System, planet Earth, etc, too. We are not connected to anything else in the universe but to all (immaterial and material) energy of our galaxy.

Happenstance notwithstanding, the scientific information can get expressed at the largest level of galaxies only, while the scientific conclusions about the whole of all original energy is that it undermined itself. The current state of the universe is that it is the infinite setting in which finite amounts of energy/matter are scattered. The word Universe is not identical to all energy. There is space with energy/matter, and there is space that is indeed just space and nothing else.

Even Einstein did not get this specific point right. He got information from the Solar System and galactic settings, and then he applied them to the universal level, as if the universal level were a scientifically intact level.

If interested:

'A religious act, not a scientific act'

https://fred-rick.medium.com/a-religious-act-not-a-scientific-fact-7adf94cd0927