I agree, there are more stages to this battle
Their Conversation after their First Awakening Combo indicates that wasn't the Best Team-Play they can come up with
So i expect the Next Improvement will be by Using their Max Awakening in Best Combination
Which will damage Big Mom greatly & most probably Nerf her significantly (Either her Body or getting rid of her Homies)
But for Final Effort (Which will remove Big Mom from this Arc just enough for the Focus to become only on Kaidou)
I believe Kid/Law will either get a New Power-Up (Adv. CoC for Kid?) or Help from others (Killer? SHs?) or a Sacrifice (Law will Die?) or Big Mom's Trauma hits again. These are the Possibilities i can think of
However i'm confident that however this Fight ends, Big Mom is gonna Unleash some Timed-Bomb, similar to Kanjuro's Last Effort & Kaidou lifting Onigashima ... etc