not sure I understand your logic on some points, there are individual examples one can give to ‘prove’ one’s own theory on all this
but ‘economics’ is a vague concept that is a product of commercial activity.
it is not possible to have commercial activity without energy consumption — this applies whether cutting down a tree to buld a wooden house, or extracting iron ore to build a skyscraper. Wood and iron is bought and sold.
Comparing basket case African countries to one another is to miss the point. Each can be affected short term by different forms of leadership or bad government. Long term they are both headed in the same direction, with similar pop growth rates
As to fuel use/pop growth:
In the 1800s London’s population was 1m, and ravaged by disease. Then they built a massive sewer system.
How? With 6 million bricks fired by coal, and shipped in by train. The sewage was moved by steam driven engines
Now London’s population is 7.5m Which neatly reflects the world population growth over the same period.
Without fossil fuels London could not have expanded, neither could anywhere else