Wow. So now you become one of these toxic Fanboys who just want to deny manga facts and post headcannon.
Let me destroy your post again.
This is Kaido receiving attacks from Luffy, Kid, Law, he uses gamma knife, in a row.
He didn't say those attacks were impressed of all. He called them tricks.
The Scabbards attacked Kaido's old scar.
Even though they knocked him down their attack didn't have enough power to open up his old wound or scar him.
Zoro's Dead Man Game
Kaido spits up blood.
He's pissed off and he tells us the attack called significant amount of damage because it scarred him.
As you can see when Kaido receives a significant amount of damage the manga tells us. Scarring Kaido is a way for a swordsman or fighter who use external attacks to cause Kaido a significant amount of damage. You can also see knocking Kaido down doesn't mean anything.
Where did you get this BS that Luffy attack is double at 100%. At 100% his attack is 100%. At 50% power his attack is 50%. When he defeated Doffy he hit him with his strongest attack. Luffy and Doffy were in the weaken state. Remember, just because you can defeat an opponent with you're strongest attack while they are weaken doesn't mean the same thing would happen if they weren't. Luffy defeated Katakuri with a weaker attack than the one he hit Katakuri with earlier during the battle. That worked because of the condition Katakuri was in at the time.