But the case simply seems to be that no one is really aware. If T'challa knew what was going down with the chieftans he'd already be on it. I feel like the omission of any explanation for these scenarios is not the omission of the government's overseer but merely their incompetence and lack of knowledge. A country collapsing has a million other things fukking up alongside human trafficking so it's not that hard to lose track of insider crime.
As to your second post, your guesses are as good as mine where Coates takes it.
Considering that the human trafficking operations are happening around the Nigandan boarder, I was surprised that there weren't any Wakandan patrols by that area, especially considering that Wakanda has been attacked multiple times in recent years by outsiders. It would be in Wakanda's best interest to be vigilant around the border area. Not to mention that, based on the reaction of the women that were captives, those operations have been going on for a minute now, to the point that they felt neglected.
I think what could've helped Coates on this one is to explain via a line or two from a supporting character, or even T'Challa himself, that Wakandan forces / authorities / resources are all over the country " putting fires out" due to the recent events, resulting in the authorities being stretched too thin. That way, the people doing mischievous shyt would def be able to slip through the cracks and do what they are doing, and there's a clear reason as to why they were able to do so for so long. The same could even apply for the corrupt chieftains.
As is, though some characters mention that Wakanda is going through major trouble...it doesn't feel like it, imho. Or even look like it, in a lot of cases. Maybe that's were the disconnect is coming from, from my POV.
iirc, The Dora Milaje were originally conceived to serve as T'challa's future potential brides and basically his private harem.
And T'Challa never treated the Doras as a private harem. IIRC, it wasn't even his idea originally (correct me if I'm wrong on that one). The only reason he continued it is because it kept the peace between the tribes. The Doras' creation was ultimately political in nature, a means for a tribe to potentially get plugged into the royal family. And the Doras, as time went on publication wise, basically have turned into an all-female unit that serves to protect the ruler and his/her family. The potential bride thing hasn't even been touched on in almost 10 years.
Meanwhile, the Doras are highly respected in Wakandan society. Those that harm a Dora can be sentenced to death. The Wakandans also respected the authority of Ramonda and Storm, even though they were foreigners. And they've rallied behind Shuri during her time as Queen, while she was the absolute ruler.
This isn't to say that there aren't Wakandans that could be considered misogynist. I wouldn't be surprised if M'Baku and other members of the White Gorilla tribe were indeed misogynists, especially due to how old fashioned they were. But Wakanda as a whole? As a country? There isn't enough on panel evidence to show that indeed was the case, unless I missed something.