Replaces the Iron ingot in the Shield recipe with either a Netherite ingot or a Diamond depending on which datapack you choose.
While making a world press the datapack button and press open folder.
Afterward, place one of these files into the datapack folder and apply it in Minecraft.
Then press done and continue on as if you were creating a regular world.
It is recommended that you put this at the top of your datapack list or else there is a chance that it will be uncraftable.