The best way to deal with atrtefacts imo is to download the artifact finder mod and the PoD patch for it, but if you don't want that then you have a map filter that shows the rarity of the artifacts owned by people (both the owners of the county and their courtiers) the holy grail is illustrious and often in the hands of a courtier so, while a little tedious you can just use that filter and check all the purple spots until you find it

Thanks I found him.