At first I read the OP and it was like "I know the outcome is pretty obvious" and I was like "Yeah I know, Kurama stomps" and then I read the rest lol.
Kurama unfortunately stomps, his bijuu dama were completely dwarfing mountains , and one they launched in conjunction with Naruto that took literally half a second prep as opposed to the other bijuu's large amount of preparation, it matched 5 mountain busters with ease. Imagine if Kurama took the time to charge his own bijuu dama. Kurama already made the bijuu his bitch before, and Gedo Mazo was only that much more powerful thanks to the 7 bijuu accompanying it. He's just out of their league.
KN4's bijuu dama decimates entire forests after being broken down by 3 giant rashomon gates, KN6's bijuu dama that took 2 seconds to charge after getting smashed in the face by a giant boulder made the hokage faces look like ants. Kurama's got this.