Not the GP but I've been in a similar position: - Be good (and fast) at Googling things. - Know your foundations, deeply. Don't memorize design patterns and algorithms: instead, learn how to arrive at them organically…
If those things are required for his role and he's not doing it, then he's not a 10x developer. There's some issues with your management. Also, just because someone has good performance doesn't mean he's an insufferable…
Not the GP but I've been in a similar position: - Be good (and fast) at Googling things. - Know your foundations, deeply. Don't memorize design patterns and algorithms: instead, learn how to arrive at them organically…
If those things are required for his role and he's not doing it, then he's not a 10x developer. There's some issues with your management. Also, just because someone has good performance doesn't mean he's an insufferable…