Story Metaphysics: World Creation?

I was reading something last night that inspired me a little to lay a foundation for the world in which my characters can exist in so I'll just put it here real quick- [22 Dec 2020]

Ummm
In a very simplistic world view, maybe for a in-story religion or mythology, the world would be constituted of the Heavens, and the Earth primarily

 I won't get into what is in the heavens just yet
But I'll say that, since it's associated with the sky, the Sun and the other stars, aswell as other astral bodies, it is considered at the very least to be a warm realm, generally
 The heavens shine down on the earth and grants it both life and heat

The earth itself has none and is dependant on this temporary relationship
Below the earth is the underworld
Needless to say, the underworld is cold: it's the realm of the dead, blahblah

Below the underworld would be another realm
And unknown realm to most, but technically equal in value to the heavens
Umm... there is nothing there, it is just chaos

I wanted to mess with the idea that.. uhh...
...Just like how many celestial bodies have cores, that the realm beneath the underworld would be a 'core' for existence

Which I think makes it interesting

In order of importance, the gods would probably decree that it goes:
 The Heavens > the Underworld > the Earth
And that's only if they include the Underworld; I'd think there'd be some rivalry there

The true order would be more like..
Wait, yeah for lack of anything else, I'll call the realm beneath the underworld 'Void' for now
So the true order would be... actually no, not the 'true' order, just a more accurate one
 Void > Underworld/Heavens > Earth

Isn't that curious, though?
A realm so far beneath the heavens is infact more important than it? Then what of the Earth, realm of mortals, that is directly under the Heavens... hmm
 I would say the Earth has a potential relevance equal to the Heavens
The Heavens is typically known for being the realm of the immortals; the gods
When mankind's era comes, the gods get shoved more and more into the background despite their might
But still, the Heavens shines down on the Earth to give it life
The Heavens is also the space where the stars and the sky are.. so...

In the end, it might be more accurate to say all realms are equal and have their uses
 The Void is responsible for the existence of the other realms but plays no role after that, supposedly
 The Underworld regulates death and chains all to the Void, maybe
 The Heavens give light to existence
Though it came from the Void, and the chaos within, it plays a crucial role once it exists
Without that light, there is just darkness, and none of the realms would be seen and attributed to reality without it
 And the Earth is the crystallization of all these things, the culmination
It might seem like the Earth doesn't contribute anything to existence, but that's because it has another role: it is the definite proof of reality; the labor of existence

So... yeah
If I had to personify the realms...
 Void is definitely a progenitor of some kind, a parent
 Underworld is... hmm..
Like an office secretary who keeps track of everything, or.. an officer who regulates law, and limits existence.. cuz otherwise, the chaos aspect of the Void would run rampant...
 The Heavens are laborers who created the environment for life to be, and will remain a constant reminder of that effort by their light and heat
Uhh.. their radiance
 And the Earth is the child for whom all previous efforts were made, and gives meaning to it all
While the other realms shaped existence, the Earth shapes destiny...yes.
Fun concepts

Now as for the whole hot and cold thing
 Heavens are hot; Earth has no innate heat but is hot; Underworld is cold; Void is innately... cold?
It's very possible the Void is actually so hot it feels cold, but there's no proof of that
Or heat truly is absent there, and could never reach... I dunno, I'll develop those ideas when I feel like it
(A reminder that the Void realm doesn't necessarily refer to space)
 The Heavens boasts being the source of all heat, of all light and of all life through their radiance

Due to the chaotic nature of the Void, even if it truly was a source of heat, it's too unpredictable to verify
In short, it's simpler to just agree that the Heavens is the source of it all and not question what is in the nothingness of the Void
Asking where things beyond the gods and existence come from is something humanity does, and suffers for

That's all I've got for now... although I suppose none of this directly relates to any of the current characters in my roster.. mmm..