Hi, after reading the title you might be confused but let me explain.

The nether, the nether is the center of the overworld, it is the core, the molten lava core in the center of the world, the reason 1 block in the nether is 8 blocks in the overworld is that if you dig to the center of the earth, dig one meter forward, then dig up you will be more then 1 meter ahead then you were, the reason lava falls down in the nether is because there is lava pools near the bottom of the overworld, and those fall down in the nether, and because the nether is the core of the earth water will evaporate because it is so hot.

The end is over the overworld, Infact it is the clouds, I know what your thinking, no it’s not I see the clouds and can build to them, I say to that, those are fake clouds, that is why rain comes from over the clouds, and why the end island look like clouds and why it is so dark up there, because it is close to space, and with night vision poitions it looks like stars up there in the end.

Thank you for reading, until next time by! And please let me know if there is any flows or something needs more explanation.