I feel like its toss up if kakashi had the tools he'd be the strongest and is the most talented, like if he was Uchiha and He could use Sharingan without losing so much chakra and use susanoo like the brothers he'd be stronger than both because he is smarter and more talented
Its still toss up between Itachi and Kakashi tho
Its still toss up between Itachi and Kakashi tho