Creating custom biome: Weirdness

Hello, I am trying to create a some what simple biome. It's supposed to look like the alpines.

Basically I want large mountains and next to it plains with rivers and very green grass. Sounds pretty simple, but I have 0 experience in creating biomes.

My approach was to create one biome that generates the mountains and another biome that generates the landscape (Like swamp and swamp hills for example)

I found the property "weirdness" which is supposed to make the biomes spawn next to each other.
However, when I generate the code for the biome, it doesn't look like the weirdness is even in the json file. 

https://cdn.discordapp.com/attachments/762647986110726145/1173549144242147408/Screenshot_15.png?ex=65800b4f&is=656d964f&hm=4093eba1f586959609745c98b29c7d9f2fec3da831787c5627c7fedf14eba332&

https://cdn.discordapp.com/attachments/762647986110726145/1173549714399047730/e70cd75747e773a615abfc29073c7c5d-ImageTwo.webp?ex=65800bd7&is=656d96d7&hm=bd48ca1ab1587680c64a24e61985a30885f388cd658156436bfec8154a2daafb&

https://cdn.discordapp.com/attachments/762647986110726145/1173552202615357450/Gro3Fe_Berge.webp?ex=65800e28&is=656d9928&hm=4f994cf54815fb0886d1be5d8d25f55276b93a2b631e905232bd317829f8b7df&

Here are some example pictures of how the biome is supposed to look.

Do you have any idea how I would go with  my approach?