having the same issue as an old closed issue #688 but in 1.20.1
tried to disable adventure module, gets me a datapack error at entering any world, and doesn't let me create any new ones. did some testing, happens if I turn off any of the modules, even setting the "book on join" to false is causing this

forge 47.2.0

what do you expect people to do without any logs

also check if it can be replicated with neoforge
#1006

duplicate of #989