I created a datapack for editing loot tables because of the complications with using some mods together. I tried to upload local file and it correctly saw that it was a datapack and it shows up in my mod list when looking at my pack. However, when I go in game to create a new world, it's not in the datapack options and when booting up the world, it's not working.
#How do I add a custom datapack for my Modpack?
river ivy
slim crescentBOT
Im not 100% sure if this works for the client, but put it in a folder named "datapacks". Not in mods or anywhere else.