Repost time.
Anybody who are saying Sanji will do 0 to minimal damage to Kaido needs to either seek medical attention or psychiatrist for treatment.
Let's do some math here.
We know that Kaido got burned by his own fire.
Sanji's Diable Jambe is stated to be 2204.444 degrees Celsius which is hotter than fire itself.
Sanji's DJ can bypass opponent's durability and burn their organs from the inside.
Sanji was the first SH pre-timeskip to ever damage a Pacifista despite how hard it was.
The Scabbards was hurting Kaido with Ryou.
Sanji is confirmed to have Ryou.
"But but Sanji can't damage Page One or Doflamingo."
Me:
Sanji clearly damaged Doffy.
You can see the bruises and the black dots coming out from him.
The same way Supernova damaged Kaido.
Sanji makes Page One bleeds in base form.
Again, the black dots is an indication of that ^^
Page One screams from RS Sanji's base kicks.
While Luffy's Gear 3rd named attack + haki barely did any damage to Page.
Punk Hazard Sanji's base kick dented the metal door.
While Whitebeard with Gura punch barely dented the same wall.
So we can assume that PH Sanji's base kick >~ WB's punch.
Next, Sanji is known for durability breaker no matter how strong they are.
Sanji damages Vergo even when his body is like a iron mass.
Sanji broke Oven's neck who is confirmed to be the most durable Charlotte.
Sanji breaking Oven's collarbone have the same SFX as rip/crack.
Sanji dented the face of the most durable Vinsmoke.
Vinsmoke Yonji
"Even though he's the youngest son of the Vinsmoke Family, he has the sturdiest (physical constitution/physique) and possesses incredible physical strength~! "
Kaido who is the most durable Yonko will probably get pummeled by Sanji with significant injuries or worse.
Sanji's Invisibility + Durability of the RS would help the supernova against the Yonko, as proven by Sanji breaking King's beak.