I had just over two years in Mozambique, three months in Tanzania, went through S Africa, Zim, Malawi many times. Forget MK’s, I had a job to keep six running 30 years ago due to parts shortages. Remember they’ve been out of production decades now and metal does fatigue, especially axles, springs and hangars. Unimogs? Good support for Mercs in most countries , but there aren’t many mogs and there’ll be very little parts support in the areas where you’re going to break down. Toyota 70- or 100-series, parts all the way through Africa, not that you’ll need many. There’s a reason NGO’s, rebel forces and terrorists use them. I did a lot of miles in them, mostly on unsurfaced roads, but you Pay your money and take your chances.
PS didn’t see one VW of any description away from the bigger cities. You can’t get parts everywhere.