I've been thinking about this, and I'm still a bit stumped. I think you want something that opens the story up, and doesn't center as much around Wakanda, which is why my first thought (an adaptation of SWAD) won't work. On the other hand, something like Enemy of the State might, especially if the story also introduces the exiled princess of the J'Bari (because I want QDJ and MCU!Shuri in the same room).
I think it's only a matter of time before M'Baku has a heel turn as well, which would be another reason to bring QDJ in, as if he is imprisoned/killed, someone will have to take leadership of the Mountain Tribe.
What I don't know yet is who the Big Bad would be. M'Baku works as The Dragon, but he doesn't have the ambition for a global conspiracy. It might be time for Achebe....