Powers & Abilities Gear 5 Luffy still isn't using his main abilities

[bzxw27]

Gear 5's main ability is fire manipulation and we still didn't see Luffy do some huge hikens and throwing small suns using it, Luffy will have the hottest flames there is, his fire attacks will make sabo's hiken look weak.
The other abilities are awakened versions of gear 2 and gear4.

 

[Fuyuppe]

It is called the Eternal Flame.

 

[bzxw27]

Now that you say that maybe it's the way to beat immortal beings? just put them inside the eternal flame?
This matches the gear naming scheme perfectly , Luffy is an engine that will turn the eternal flame into an eternal sun