How smart does an Insufferable Genius need to be?

I was looking through Insufferable Genius and reading some of the examples I feel that some of the given characters are just insufferable and not really geniuses. The example I saw that got me thinking about this is the following.

• My Hero Academia has Bakugou Katsuki, a Genius Bruiser and The Rival to the main character. He spent the first 15 years of his life being showered with praise about his wits, quirk and prowess in battle, to no one's surprise, he has a brutal Hair-Trigger Temper, gets violent and shouts at the slightest tease, and has varying degrees of Psychotic Smirk in his face whenever he fights. He gets massive pieces of Humble Pie thrown at him during the entire run of the manga, including the guy who he always looked down defeating him, The Ace of the class basically ignores him because he sees Midoriya as the real top of the class, various character show potential to defeat him and even getting kidnapped with Midoriya leading a rescue group to find him.

While he is skilled and fairly smart it would be hard to argue that he is easily at the head of the class in any particular facet. Further, except for with Midoriya, he does not really go around saying that everyone is worse than him, or that he is the best, he is more of a general Jerkass.

There are some other examples that I feel are like this. So how much smarter of better does a character need to be than the rest of the cast or location to count. Does he need to be at the head of the group? Does he even need to be smart? Though that last feels more like it would fall into Know-Nothing Know-It-All.

They need to be smart enough to regularly be right, and they need to be insufferable about what they're right about.

If they're just general jerkasses they don't count. If they're not correct in their genius area most of the time they don't count.