probably ike? cause he has a playlist of his current inspirations, and the tracks on there are pretty good vibes. I dont know much about contemporary, mainstream rap- I mostly listen to N9na, Hopsin, Yela, Posty, and 90s rap.
I would just tell him to keep following his inspirations, but to also not be afraid to branch out and try something new. A lot of underground music is discovered for being different or saying something that resonates with a lot of people.