Cave Generation

(Fabric 1.21) I've extended the world depth to -128 from -64 and terrain and all generates down there, but only the really thin and noodley caves. What exactly is it that im supposed to edit to make the real big caves also able to generate down there? I tried adding custom carvers to my_pack/worldgen/configured_carver/deep_caves.json, but it does not seem to change anything in the world generation, even if I tweak the values to the extreme? Does the file need to be named overworld.json or is my file structure overall incorrect?