I think he should just combine G4 with his CoC. 4 gears and one with multiple forms is more than enough. He’s about to fight him with a full stomach so he’s about to get a Kid Goku zenkai and win.
Next arc we get Awakening hopefully.
It was never confirmed. A lot of people at another forum I go to thought it was either Shiki or somebody we would meet in Wano but the second option is pretty much out the window at this point.