Gamerule? Cool! Config file? Even better! Permission node? SURE!
Just- PLEASE add a way for it to be disabled. I host a server using a 1.20.1 pack which includes the Deeper And Darker mod, and every day I get complaints about the Catalysis enchantment. It can even spread sculk in OTHER PLAYERS' CLAIMS!!! I've looked everywhere and could not find a way to disable the enchant, so please, add a way to disable it.

Why are you letting the players even have the enchantment in the first place? Disabling the enchantment would render the purpose of the enchantment entirely obsolete and therefore a waste of an enchantment item.
In my opinion, I think it is better to just have it removed from the server altogether so no player can get their hands on it.

Why are you letting the players even have the enchantment in the first place? Disabling the enchantment would render the purpose of the enchantment entirely obsolete and therefore a waste of an enchantment item. In my opinion, I think it is better to just have it removed from the server altogether so no player can get their hands on it.

and how exactly would I go about doing that

Datapacks should allow you to do so via removing them from the loot tables of chests, and the enchantment from enchanting tables.

this is a key feature of the mod that we dont plan on disabling.