Well I still think that BB's awakened Yami fruit combined with an awakened Gura Gura no mi will prove to be too much even for Nika mode Luffy; therefore I think that the Straw Hat's meeting with Dr Vegapunk will reveal to them a secret aspect about Devil Fruit powers that is different from awakening and this is going to be Luffy's leeway into Gear Reverse which in my opinion will not necessarily be stronger than 5th but will be very situational and helpful to Luffy specifically against a foe like BB, but that Gear 5th will remain his main trump card even towards the final battle(unless BB is Luffy's final adversary in the series of course)