it makes perfect sense. kid's haki isnt up to snuff and he has coasted by on overwhelming force, a really great devil fruit, and ruthless forward movement, but he's arrogant and thinks he can fight a war alone.
Hes a strong contender in pretty much every scenario except facing the top tiers of the universe with just himself and his one ship's crew. he's not beating Big Mom without Law's help, just like Law wasn't doing it alone without his help. Against Shanks 1v1, or his one ship vs every affiliated crew Shanks can bring to the fight, he doesn't really have a chance.
im not trying to troll but even if law and kid were equal to luffy, luffy's not beating kaido this way either lol. like imagine if instead of starting with a 3 point stealth raid on onigashima and surprising everyone when they werent ready for a battle and letting 20 other guys soften up the yonkos first, they just charged in the door and started fighting, and kaido got to survey the situation and attack on his own terms.
theyd be fucking dead. kid is just an idiot charging in the front door.