The time for powerups has ended. Naruto could at this time develop chakra chains considering he is Uzumaki but I doubt anything will happen. It is time to only fight using the powers they have.
tell me more. ur logic is flawed. so sasuke doesn`t use some powers in kaguya fight, but he uses them after kaguya is defeated. so naruto doesn`t need to pull his avatar ? won`t the bijuus go inside naruto after he saves them for the 2nd time ?