Also, another thing about the idea of Kaido "turning good" or however people put it:
I was thinking that maybe it would be alright because a lot of the Naruto villains took a similar path, but then I realized that almost every Naruto villain who turned good was set up to do so from the start. That is not the case for One Piece villains.
Nagato truly wanted peace, yet he lost his way following Yahiko's death and Obito's manipulation. His goal never changed, just his methods. He was corrupt in a different way than One Piece villains usually are.
Sasuke was blinded by vengeance and later on wanted to make the Shinobi world better through his twisted ideas of what a good leader should be like.
Madara wanted to find a way for everyone's dreams to be realized without conflict, but he felt it was necessary to do so by force.
All of those villains had it in them from the start.
People like Kaido, Doflamingo, Rob Lucci, Enel...I mean literally every One Piece villain had either selfish or corrupt motives.
Kaido literally makes people his slaves just because he thinks that's what you get for losing. He wanted to create an impeccable army of monsters, not for altruistic reasons but because of his own motivations.