To add to the above, SA corruption is more than a problem of money not going where it needs to go, it also affect public utility. The electricity state own utility (ESKOM) is incredibly indebted and severely under capacity and this greatly reduce SA potential (it's hard to justify building a plant when you don't know if you'll have electricity most of the days and need diesel generator just to keep the light on).
The previous president, Jacob Zuma (2007-2017), was extraordinarily corrupt. The ANC recently replaced him, but the replacement barely managed to get enough vote to do so (iirc the next closet contender was Zuma wife who was widely expected to shield him from corruption probe). His replacement, Cyril Ramaphosa, is seen as pretty clean, but he can't get anything done since the ANC is stopping any serious reform attempt. At the same time the ANC is almost impossible to replace politically since they still are seen as the group who stopped apartheid. The other party are either seen as too white or are very radical, demanding seizure of white land/property, similar to what happened in Zimbabwe (and you can look up that to see how disastrous of a policy that was). Covid is not going to help this situation at all.
SA is a interesting case, it was and still is the largest economy south of the sahara, so aparthied did some things that the rest of africa is having a hard time repeating, but it's paying the price for this right now and it's preventing it from moving forward. I think the biggest lesson to draw from it is that racial policy don't work, apartheid favored white and that left a massive problem for the futur generation, now the ANC is favouring black and incompetent people are getting job they should never have obtained in the first place. As an asside, there have been more and more case of racial profiling and rioting as the economy contracted, but not in the white vs black sense but in the south african vs other african sense, racism can exist even without difference in skin colour.