Otherwise, you can just use it for fun: gift a doomdiver to your friend, so he will be shooting manually. You can use this ability wisely and gift some of the most micro intensive units. Those unit cards disappear from your interface and they come under control of your ally until the end of a battle. During tactical battles you can 'gift' some of your units to your partner. Consider playing on a higher difficulty setting You might beat grand campaign, before Archaon even shows up. It is significatnly faster, than singleplayer, because there are two players achieving the same victory conditions.
It is safe to assume, that TW:WH works the same way.
844 A Total War Saga: Fall of the Samurai.
