They´re not inherently different perhaps, but that doesnt change the fact that they are very different as characters.
Whitebeard was born to basically nothing, a shitty island, after that, he built his own way as a pirate, working as Rocks´s right hand man and eventually building his own crew and empire, an empire so strong he was seen as the ¨Ruler of the seas¨
Katakuri? He was born and inherited the fruits of Big Moms empire, and yet with Big Mom gone, he can´t maintain it. Can you imagine Katakuri trying to take over and take over Fishmen Island for example? Obviously not. And when Big Mom was alive, she and Kata didnt have anything close to a partnership like Roger/Ray Vergo/Doffy. It was simply submission on Kata´s part.
Yes, he shares the goal of wanting to protect his family with WB, but so does like, almost everyone, no?
Ace before he met was Whitebeard was already an established captain, and was attempting to kill WB, King was a nobody before he met Kaido. And when Ace saw Whitebeard going out, he disobeyed his own captains orders to fight Akainu. King saw his crew lose a major war and was content on spending his days drinking with Queen.