Comics publishing has become so nostalgic and traditionalist that it's starting to devour its own tail. The books keep retelling variations of the same tired old narratives, over and over, due to a combination of creators wanting to give "their version" of an overused tale and editorial not willing to risk alienating existing readership by stepping out of their safe zone.
And when they do take risks, they often undercut it by clearly signposting that the "bold new direction" will be temporary, so that the core readership doesn't decrease too much.
In the case of T'Challa, the stories hinge around him having difficulties with his role as King. He either has folks from the outside (often Killmonger and/or Klaw) trying to depose him, another tribe from the inside fomenting revolt, or is confronted with a hard choice that makes him doubt his ability to be king.
Lather, rinse, repeat.
And when the scope of his responsibilities expands to multiple star systems, what does he do?
He runs back to Wakanda because he doesn't feel worthy. He passes responsibility to nuBaku, someone who has no training in governance, and swans off.
But hey! Some idiot in tights is doing bad things! He can handle that, right? Well, with the help of his ex....