These two are the strongest protagonists in the entire Pokemon series:
-They were able to beat EIGHT major villains (Lusamine, Guzma, Archie, Maxie, Cyrus, Lysandre, Ghetsis and Giovanni), six of which had come from dimensions where they won. Not to mention that the latter six had Legendary Pokemon and two Mega Evolutions on their side
-They were able to beat three former Champions in the Battle Tree (Cynthia, Red, Blue)
-They were able to take down Ultra Necrozma (who has a higher BST than Arceus)
-They were able to become Alola's Champion