Need some help making the Deep Dark generate in a modded dimension

Context: Been working on a (1.20.1) modpack with a floating islands overworld world preset, which necessitated the existence of a dedicated cave dimension, thus I having a mining dimension mod. I've figured out moving structures into it, but the biomes like the Deep Dark have me stuck. I feel like I've edited the json for adding it correctly via datapack, and I don't think there's anything in the noise_settings or dimension_type that would effect generation of a new biome. I have a datapack path as follows: (folder/root name) > data > mining_dimension (the namespace of the mod) > dimension > mining.json ("mining" is the name of the dimension in question) And inside that json, I've modified it from a fixed single biome (containing the mod's "mining" biome) to a multinoise just to add the Deep Dark to it (exact json file is linked). So I'm unsure how to proceed. There might be a step I'm missing.