Netherworld

While the center of the netherworld is hell, the Netherworld as a whole is pretty colorful place, albeit with moreso of a dark and grim tone, but nonetheless.

(If you want to get what I mean, look up either Dormammu scene from the Doctor Strange movie, or the realm of the monsters from the Moana movie. Or both, idc)

Nonetheless, in comparison to the Aetherworld, it is much grander in size, because unlike the Aether-World (which has heaven as its clouds), the Netherworld has hell as the core of the planet.

Size
The Center of the Netherworld superplanet is hell, the 'community center' of the Netherworld. Its dwarfs the size of the observable universe by a hundredfold, and it is the core of the planet, the core-to-planet ratio similar to Earth's ratio.

Environment
Lava and Flames at the core of the the godly planet are superdimensional, and as a result is so potent that it bypasses most to all resistances/immunities to heat. Even Summer, who is a godly pyrokinetic herself and has no-selled hellfire techniques before, was pulled from the flames and barely alive upon falling in.

At the surface, the supernatural heat is much more forgivable, and people with hellfire immunity can last in it with minor pain.