By your own admission, it was far better than the current alternative. I don't judge good or bad based on an imaged alternative of some idealized world, I base it on real choices that are on the table - i.e. Apartheid vs. Xhosa tribal rule. By that standard, Apartheid rule was a net good.
Yes,it surely seemed better for whites 40 years ago than it is today. But I can’t be 100% certain about blacks. For example: the murder rate in SA today is just about the highest in the world. So the question is...what was the murder rate for blacks back then vs today? My guess is that it’s worse today. also...standard of living (housing,nutrition,etc) for blacks today vs 40 years ago. My guess is that its worse today...but I can’t be sure.