It's not that he wants a strong DF, really anyone would want a strong DF honestly.
It's that he then went on to lecture Luffy about Haki being the best ability despite spending around 8-10 years (I forget how long it is) begging for a fruit.
Because Kaido tried to fight the WG, and couldn't win even with his level of Haki and Devil Fruit. Kaido was training Luffy to be the new Joy Boy in Wano.
When does Kaido talk about Haki triumphing all? After Luffy turns into Gear 5.
Kaido is saying: "I have one of the world's strongest Devil Fruits, and some of the strongest Haki, and even I couldn't do what Roger did. Do you have a shiny new toy? Yeah, your Fruit Awakening is strong. But, Imu, and the Gorosei? You can't beat those guys with magic stretching powers. Only your Haki can actually fight the monsters at the pinnacle of this world."
Kaido thought with a strong enough Devil Fruit, he could conquer the world. He was wrong. Kaido in Wano has accepted he's evil/doing things the wrong way, and is just trying to create the new Joy Boy.
IMO, Kaido thought Ace was Joy Boy, and has been depressed since his death; I think the suicide hobby came after Marineford.
I also think Kaido talked to Shyarly when he met Jack in Fish-Man Island, and Shyarly told him he would die fighting a Hero in Wano. Kaido's suicidal because he already knows when he's going to die, and hates fate and is trying to change it through suicide.
Kaido was warning Luffy that Gear 5 wasn't enough to beat the monsters Kaido met on God Valley.
And, he was right: Luffy's Haki was too weak, and when he punched Warcury, he got a big boo-boo
Both times Luffy attacked, once in Base, once in Gear 5, both time with Gear 3, he didn't do shit.
Kaido was thinking to himself in Wano about Luffy: "Bro, I've fought Topman Warcury in God Valley, YOU ARE NOT beating him with Rubber Jesus powers. Gotta get that Shanks' Stack."
IMO, this is how Teach beat Law, too: Teach wiped him with CoC.
I think Kaido's fought all the Gorosei before... maybe Imu, too. Kaido's at least seen GunkImu on God Valley, tho.