Theory:
The gomu gomu no mi isn't a paramecia, rather it is a special mythical zoan
The fruit the gorosei are talking about is presumably the gomu gomu no mi. Its either that or kaido's DF and idk why they would lie about the name of the seiryu fruit as its already known that this fruit is overpowered.
If the gomu gomu no mi isn't the true name of the fruit, it really begs the question what this fruit's power really is. Because it literally gives Luffy's body the properties of rubber. So what else could it be? Because its not going to be something trivial like the plastic plastic fruit or a rubber logia or anything like that. None of that would justify lying about the fruit's name.
imo the gomu gomu no mi is actually called the devil devil fruit model: sea devil. Luffy is literally the sea devil. The reason this fruit's name is hidden is because it is deeply tied with the lore about the will of D and joyboy. I think that similar to katakuri's DF being a special paramecia and blackbeard's logia being a special logia, the sea devil zoan is a special zoan in that it doesn't have a hybrid or a full beast form.
However the gomu gomu no mi is still a zoan and will have a zoan type awakening, not a paramecia awakening. With awakening, Luffy will draw out the full power of the sea devil fruit which will give him some sort of transformation.
I also think that red hawk is tied to the sea devil's power and with awakening, Luffy will have access to fire punches casually.