Hidden artifact appearances in dragonflight

I’m hoping to start farming for the hidden holy paladin artifact appearance called Lost Edict of the Watchers soon, but I don’t want to farm for 4 hours just to realize that it cant drop.

If I were to create a new paladin, would it still be able to drop? Or do I have to do it on my existing paladin who I had back in Legion?

and also, do I have to be specd as holy for it to drop as well?

It should. The only artifact skins not available are the mage tower skins.