Need somebody to help me who has good knowledge on biome generation.

I mostly understand how biome gen works in MCreator but I want to know how you'd make a biome generate smaller?

 I am using a custom dimension that's just void and nothing else. I have three biomes with all the same generation settings except for the temperature parameter which I've set to make 2 biomes take up 50% of the world and 1 main biome to take up the other 50%.

It all works as intended but I want to learn how to make said biomes generate smaller, because right now you have to walk 2k blocks to get to the next biome which is equally as large. any help? (Regular forge on 2023.3 MCreator)