What the factor prevent Europeans from conquering much of African prior to the 1800s?

Prior to the 1800s, several factors prevented Europeans from conquering much of Africa, including the continent's diverse and complex geography, which included vast deserts, dense jungles, and formidable mountains. The presence of powerful and established African kingdoms and empires, along with their military strength, also posed significant resistance. Additionally, Europeans faced challenges such as diseases like malaria, which decimated their ranks, limiting their ability to explore and establish control over vast territories.