You are clearly forgetting the main advantage of gunpowder in those days, morale. Not actual physical damage.
Sure, but you're assuming that "advantage" should be decisive. Why? It clearly wasn't in history.
I mean, I imagine arrow poison was quite frighting to encounter as well. The thought that you might survive a battle only to literally poop yourself to death sounds pretty scary in a time when medical knowledge barely existed. Should we force the game to reflect that too?
There are no strength figures and very little information on the "main" battle of that Kongo-Portugal war.
You can't trust "strength figures" from the time anyway. They were often embellished or exaggerated, particularly when Europeans fought non-Europeans. However, the Kingdom of Kongo proved quite consistently successful in resisting the Portuguese up until its final defeat in 1665, a century and a half after your attempted invasion.
There is nothing objectively irrational about it since it follows the in game logic set by the game's start point, that being something similar to real life history from ~1440 onwards (like African technology),
The game logic is unrealistic in terms of the weight it accords to fairly minor degrees of technological superiority. The differences between a "feudal" army (like that of the Kingdom of Kongo, using the term feudal very broadly here) and a late medieval army (like Europe in 1500) was not that big at all. There is only so much which can be done with sharp bits of metal, guns which fire 4 bullets a minute an army still organised around levied peasants and mercenaries.
It's like saying there's a comparison between in game African nations and in game European nations and also modern African nations, who have cold war technology and modern European nations.
No. It isn't at all. Today, in an age of high performance aircraft, artillery which can flatten square miles of terrain in seconds and computer guided missiles, technology is considerably more important. The technological differences which we're talking about here are simply not that significant in comparison.
Those sub saharan nations had hundreds of years of technology to catch up on.
Let me explain to you why people are calling you Eurocentric, and why they're
objectively (since you like that word) right.
You've assumed (as does the game, for that matter, but the game is forgivable in that it's just a system trying to abstractly represent things) that technology follows a linear progression through history which can be expressed in the form of stadial time. What is that model of history based on?
Oh right, it's based on what happened in Europe..
In truth, the amount of "technology" present in different societies at different times almost never accords to a single point in European history. Technology at this point is just the stuff that works in a given time and place. The various African military systems of the time may look inadequate if you define advancement by the availability of guns or metal armour, but that doesn't really matter. What matters is whether it worked, and historically it did.
At the start of the EU4 timeline, the most powerful and successful military system on the planet was developed by people who lived on the Eurasian steppes and whose way of life had been essentially unchanged for thousands of years.
