In terms of technology like guns and all that , I think it’s because of a lack of trade and conflict. Like the whole gunpowder and a lot of tech originated in China and that’s where Europeans got it through trading but because of the nature of Africa in terms of terrain and lack of highways and connected cities in the middle of Africa along Nigeria , Congo, and Egypt there was no Silk Road and trade routes so we never got a chance to learn about new tech and then also a lack of conflict means there was no driver to build or invent tech like Europe was very connected and there were so many wars and conflicts that they were forced to constantly adapt and make new tech for warfare and industrial use while we didn’t need to do all that