Setting the worldgen_settings.json file to have "seed": 0 causes the game to interpret it as ASCII and automatically set the seed to literal 48 instead of a random seed upon generation.
MC-222671 Datapack World Gen seeds not randomizing at all
MC-223045 Seed "0" does not use the world seed in custom dimensions
MC-44944 "0" is not handled as a valid seed
MC-209001 Typing seed 0 no longer generates a random seed