So he didn‘t even believe he would‘ve killed him + he believed in the prophecy that Kaido could only be beaten 20 years in the future.
Yeah, which is odd considering Oden had all means to kill Kaido, I mean he was really about to.
Kaido survived DR Xebec without a scratch while literally being a cabin boy. Obviously different situation and Oden actually managed to leave a scar, maybe he would‘ve opened again after a second time and kill maybe not, but as you said it kinda tanked Kaido a bit. But the Rocks FB made him look cooler in someway.
Rocks Kaido was fun to read; not the mess we got in Wano instead where Kaido's character was literally all over the place.
On the other hand, DR Xebec was easily handling Dragon Kaido and threw him on a mountain. The entire part is complete bullshit since neither of them even tried to understand why their captain suddenly changed. I mean, I get Kaido being a bit slow but Big Mom and especially WB thought Xebec betrayed them when he even grew demonic wings after he fought some demonic blob lol? They just left the island altogether.
Let‘s be honest his crew is dogshit, bar him and King.
Even King is shit when it comes to his skillset.
This dude got massively carried by his Lunarian power - no CoC, no awakening. It makes things worse when we got 7 Lunarian Seraphims the next arc, with both Lucci and Kaku unlocking their freaking Zoan awakening during the timeskip lmao.
I get why Marco didn't show that much maybe because Oda still has some plot purpose for him in the final saga but there was no excuse why King didn't have CoC or awakening at least. Just look at Katakuri. This dude was extremely skilled. Logia-like DF, Future Sight, Awakening AND CoC. All Calamities needed 2 extra chapters for their Awakening. Okay, I mean, King doesn't have to be a CoC user - although it's extremely weird how he talked about kingly ambitions to Zoro but didn't even have it by himself lol (just like Kaido when he talked about Zoan Awakening but didn't have it either) - but Awakening is THE requirement.
He literally sat in an isolated county for 20 years and doing probably nothing, it had to be his strength that gave him the highest bounty to all living pirates at least.
It's also weird how Oda never bothered to show how many "top tiers" were even defeated by Kaido.
He's meant to be the WSC - a fraudulent title since Loki and Imu exist - and the guy who'd win any 1vs1 battle but his real top tier battle is against Oden and it ended with a stupid hostage situation which was extremely benefitial to Kaido.