Travel to South Africa and Namibia

This year we have already decided where we’ll go on vacation and the destination was South Africa and Namibia. We are currently planning our route, lodges and campsites where we go to bed, having bought the flights and book a jeep 4 × 4 with a tent top.
The dunes of Sossusvlei desert in Namibia
As will be my first time in Africa (apart from my trip to Morocco), also doing camping, I would like opinions and advice from travelers who have been in Namibia by road with a 4 × 4 to tell us their experiences. Some of the questions that occur to me right now:
How many times had to change the wheel?
Is it safe?
Any elephant they dismantled the tent at night?
Are there many mosquitoes?
“The lions are dangerous?
How many pictures will be able to do in 3 weeks?
Roads in Namibia
At the moment our route passes through South Africa visiting Johannesburg a couple of days, then spend five days in Cape Town to visit the coast, the Cape of Good Hope and try to see whales, sea lions, etc..
Fly to Windhoek and from there we will drive 4 × 4 to the Waterberg Plateau Park and Etosha, where we would sleep 3 nights in the park. Then continue north to sleep in Opuwo and Epupa Falls a total of 3 nights.
Hence the idea is to arrive in two days at Swakopmund and Walvis Bay to enjoy the “beach” and dunes. Although we leave the dunes by the end of the journey where we will finish in the Namib Desert and the dune 45 we hope to go to see the sunrise.