They are all susceptible to manipulation through flattery, and non-narcissists can see and take advantage of this. But they divide into two groups. The first comprises those who do not recognize this in their own self. So they are most vulnerable to it. The second comprises those who DO recognize this in their own self. This makes them less susceptible to it (though not impervious), but, crucially, more capable of using it and of recognizing it in other narcissists.
The second type are the most dangerous of all. They are far better at getting what they want, and they achieve it by manipulating it out of the first type. Putin is the archetype second type. Trump, the model of the first.
You can understand a lot about how political reality operates by learning to recognize this principle at work. Especially (though not exclusively) right-wing politics. (The authoritarians on the left are more likely to have delusions of grandeur in Great Moral Purpose instead of vulnerability to flattery as their defining character weakness.)
Anyway, you can tell that (again, unlike Trump) DeSantis is the second type because he is doing what second types do to Elon Musk, who is the first type.