The Kongo Shall not Perish

In our world, the Kingdom of the Kongo was subjugated and ultimately abolished by Belgium. However, what if it survived? Though it's survival sounds like such a strange circumstance in our world, these events together led to the survival of an Independent Kongo.

Justification
While Africa was colonized, one country in Africa did survive colonization, and that was Ethiopia. It had survived by trading with their attempted colonizers rivals. In this timeline, Kongo survives and westernizes via trade early and defeats attempts to colonize them.

Point of Divergence
Joao I of Kongo not only converts to Christianity, but also purchases the recipe for gunpowder, producing primitive gunpowder weapons, "hand cannons." He also tells his people to adopt ways of the alien culture, saying that his nation must not be either isolationist and stubborn, nor over reliant on the Portugese aid, saying that his nation must do whatever possible to survive. This causes a ripple effect that would help Kongo survive for centuries.