Did Sanji even go all out too?
Did he use any substantial attack?
King has attacked Sanji 3x and failed to look like he's way above Sanji.
A brief clash can showcase how each fare to one another.
We saw that :
Sanji COA ~ King
Zoan King probably didn't Damage Sanji (if he did then it's not that serious)
Speed is similar.
(Reminder King onky grabbed and landed a hit coz Sanji wasn't paying attention much.)
Form those we can already say Zoan King can't beat Sanji. Hybrid form is his only hope.