Of course it's too much for Marco to take on Kaido's two top commanders at once while protecting people from them. Doesn't negate the potential fact that Oda is simply portraying him as stronger than both of them individually whether in hybrid or not. It's Whitebeard's right hand man who we're talking about here and he shows clear superiority over both King and Queen during the whole chapter. I doubt the author would draw King, if not scared, certainly worried as his enemy approaches him... twice. King completely amputates Marco's wing and he not only doesn't give the slightest fuck but counters by sending him flying and then kicking him as King can't do anything to prevent it.