ELI5: How did materials mined from Namibia affect the outcome of the South African Border War? How do both companies and rebels make money to fund wars this way?

From what I’m looking up, the whole “blood diamonds” thing didn’t play a massive role in the outcome of the South African Border War. I find this hard to believe, considering how rich in diamonds and uranium Namibia is. Did south africa really not profit from mining these materials, and did SWAPO (and allies) really not take over these mines to fund the resistance? Did mining influence the outcome of the South African border War at all, and how?

Also, a company called de beers apparently bought some mines from the south african government during the war, which remained in operation (despite the UN saying was super illegal) during and even after the war when Namibia finally gained independence.

How can this company make money doing this during a war, eve if it’s illegal? De beers said after the fact that they would never sell diamonds mined from conflict zones, because it would incentivize and fuel conflict in those regions (even if they were the ones selling them and not rebel groups). How does it do that?

Bonus question: If a rebel group were to take over one of these mines, to whom do they sell these resources to make the money they make?