One of my favourite things about the Duel Monsters anime's portrayal of the Kaiba Brothers is how well the writers executed the contradicting nature of Seto being Mokuba's role model despite Mokuba being the morally-sound one Seto heavily relies on to balance out his attitude so the life they've built for themselves doesn't implode on them again
(season 3 in Japanese sure did not hold back on nonstop providing the puzzle pieces for that "background" world-building and character explorations)
Seto is Mokuba's role model all the way in terms of determination and unabashedly being yourself, even if the world is against you for it:
But it's hysterical to me that with, like, 90% of the ways Seto actively GOES ABOUT these things, Mokuba's like:
This is such a hilariously consistent thing between these two. BOTH of them are written to be aware of that and that's what makes it work lol
Seto KNOWS that Mokuba needs to work backwards with the attitude he's being exposed to on a daily, but he's not too worried about it because he also knows Mokuba has long figured out for himself that he doesn't wanna act like that™ while still seeing his big brother for the hardworking, determined, and authentic person (with a deep down [and ngl, sometimes DEEP DOWN] heart of gold™) he is. For the better and the worse.
And what's best about this is that this is an unspoken mutual agreement. They never talked about this, it just happened naturally while growing up lol which keeps them in this low-key hilarious status quo of Seto trying to be an example for Mokuba on how to stand your ground in life by more-often-than-not utilizing jerkish methods towards everyone else,
And Mokuba then thinking to himself "Nah Bro, I'm not gonna do ✨️that✨️, but I WILL take note of your good intentions, though 👍"
Which, in turn, means that Seto is, in fact, 100% succeeding at teaching Mokuba to stand his ground on being determined and unabashedly himself. Seto's merely doing so by serving as a well-intentioned negative example that Mokuba doesn't want to emulate in anything but grit lol