This is a simple Datapack that I made because I was interested in the idea of having The Nether and The End dimensions flat while maintaining some of the features from the respective dimension.
If pre-installed in your world it will set the default gen type to superflat regardless of what world type you chose.
Major changes:
Overworld:
The Overworld generates like the Superflat Overworld preset, but unlike the preset, no lava pools can generate, the Overworld generates like the classic superflat, with only 1 Bedrock layer, 2 Dirt Block layers and 1 Grass Block layer.
Now all structures can generate below Y= 0 (Mineshafts can't spawn, even if the bounding box can).
The Max height of the Overworld was extended from 384 blocks to 768 blocks, making possible to snow, obtain powder snow and generate ice on the Plains biome.
The New Overworld Generation
Snow Altitude
The Nether:
The Nether generates with only 1 Bedrock layer and 3 Netherrack layers.
Some features can still generate, like blackstone patches, gravel patches, brown mushroom patches, red mushroom patches and fire patches.
All structures can generate fine.
Lava is considerably scarcer and crimson related stuff is still possible to obtain via the Hoglin Stables Bastion Remnant.
The New Nether Generation
The End:
The End generates with only 4 End Stone layers.
The End Dimension currently is structureless.
After the death of the dragon you can trigger the respawn mechanism of the dragon to respawn all obsidian pillars.
Seems that this End looks more like The End from 1.0 - 1.8.
The New End Generation
The End With All Structures Generated