you cant have more then one dimension per name space

heres the data pack i ziped the folder so extract it before use

Your other dimensions simply have JSON errors, as the log shows:

[15:06:22] [Render thread/ERROR]: WorldGenSettings: No key seed in MapLike[{"type":"minecraft:multi_noise","altitude_noise":{"firstOctave":-7,"amplitudes":[1,1]},"temperature_noise":{"firstOctave":-7,"amplitudes":[1,1]},"humidity_noise":{"firstOctave":-7,"amplitudes":[1,1]},"weirdness_noise":{"firstOctave":-7,"amplitudes":[1,1]},"biomes":[{"biome":"minecraft:plains","parameters":{"altitude":0,"temperature":1,"humidity":0,"weirdness":0,"offset":0}},{"biome":"minecraft:ocean","parameters":{"altitude":0,"temperature":-1,"humidity":0,"weirdness":0,"offset":0}}]}]

Fixing these resolves the issue