This mod adds a way to enable biomes on vanilla flat worlds, which means you get to have biomes while also modifying the built in layer preset of vanilla minecraft.
There are 3 biome presets, type the one you want here: 
(World -> Customize -> Presets)
The presets are:
The latest version was tested on all versions 1.21.3 to 1.21.10 but will likely work for future versions as well
(Does not work on 26.1)
