I've been watching the Ebola outbreak in Africa since 2018, specifically the Democratic Republic of the Congo (DRC) where it borders Uganda. The WHO has said the same thing there about not limiting international travel or trade. Uganda imposed restrictions anyway and has been mostly free of the ravages of the disease. When a case does show up, they are quick to contain it and all the associated people. It turns out that in those cases the person crossed the border in a place the government didn't know about. (As in illegal alien status). In that disease outbreak, WHO was slow to do anything and claimed that it needed more money. Several nations ignored WHO and provided the help they could which did far more to control Ebola than anything WHO did. I don't know if there is any corruption, but it does seem that the organization is not doing what it was originally chartered to do.
And as for China buying into Ethopia, yes, they're doing it and setting themselves up for a permanent presence in Africa. Even Namibia on the opposite side of Africa from Ethopia is trying to contend with the Chinese and has sent several high ranking officials home. Keep in mind that Africa has a lot of natural resources and China is poised to be the primary controller of these resources.