Custom Biome issues

So I'd like to have a custom biome for a build I'm making (basically just changing the color of the environment, not any terrain generation stuff). I've followed multiple different tutorials, but whenever I try to load my datapack in my current world, I get this error message (See Image 1), and when I put it in a new world, I get "Datapack Validation Failed!". I've checked and re-checked my datapack folder structure multiple times, as well as the json file, but I don't see what's wrong... I also linked the datapack structure and the json file in the images if that helps I'm probably just a moron, sorry if the solution is obvious