Africa overlander(offroad) details (botswana/Namibia/South Africa

Hoi

Can some advice how to load/which maps toe load to get detailed Africa maps? For overlanding (offroad), like sand way. etc. The free map has something but you need to zoom that deep that you can't plan your trips.  Any advice on this would be great.

The aim is to go to Namibia/Botswana/South Africa next year.

Chris