Grail = Darkseid lite = someone we can match WW up against but without making Darkseid look less because he’s being beaten up by a girl.
Don’t believe me? Look at the way they found an excuse to not have WW fight Black Adam in Doomsday Clock.
Diana can beat up Faora, but not Zod. That’s crazy talk.
And if anyone is tempted to post pics from the first arc of Superman/Wonder Woman, be prepared for me to post from the same book to show Diana repeatedly getting trashed by Doomsday.