More diamonds

So actually I don't know how worldgen in datapacks work I am trying to make an datapack that makes it so diamonds also spawn above y level 0 and in rare chances they have little bit big vein I know this part of ores come in only world gen because I have seen an datapack do it but that datapack do to every ore except diamond and netherite and I have tried to replicate that datapack but I was not able to that for datapack for making it work with diamond ores