To address a misconception,literacy rate measures the capacity to read.
Whilst it is the gateway to knowledge acquisition,there's a wrong but common belief that literacy rate is a measure of intelligence or academic capacity.
That said. R & D does happen in Zim but not in the context of the technology that you mention. We've committed alot of R & D cattle breeding, seed production, tobacco crop and were actually eaders at some point. There was significant research done in those. There are also some sponsored Zim researchers in Malaria and HIV immunology.
It all depends on a nations priorities. These can be supporting the strongest part of the economy(agriculture) or the critical issues like health (HIV/Malaria).
When it comes to other fields like engineering, computer sciences & other sciences, there may not be much being done because it costs way more money and is therefore just not a priority.
We also have SIRDC which is the official government R & D institute and is the primary recipient of government research grants. It does some work and is known for its pre-fab materials that caused some waves at some point.
Zim has done alot, you just need to do your research.
We're not infinitely behind at all.