This may be behavior caused by the 1.18 experimental modpack. However, when generating a world with certain features tweaked or turned off, it appears the config is entirely ignored.

Turning off Full Obsidian Caves or Web Caves does not work, modifying biome size is also entirely ineffective it seems.

I suspect this issue may primarily come from how the 1.18 experimental pack modifies cave gen, but havent tested it yet without the datapack as I'm currently tweaking a private modpack.