Youtuber Quadmension created a video showing a simple way to plan and make biomes in the Unreal Engine world plugin called Voxel Plugin. Coloring a flat terrain to show Biome sizes and positions is a great way to preview how the entire world would look before starting on the shaping part within the voxel graph. Take a look at the video about voxel plugin biomes.

The only addition is that there is a multiply by 100 node after the 2D perlin noise fractal node so you can use whole numbers instead of decimals on the height splitter.

Also check the terrain generation guide for Voxel Plugin