Rate my itinerary for a self-drive trip in South Africa (Garden Route) and Namibia

I'm going this July, but right now the only thing I've booked is international flights in/out of Johannesburg. Wanted to get some opinions on my tentative itinerary before I book any flights within the region or accommodations.

I'm a 25M fairly experienced driver, and I have driven on the left before on a scooter in Indonesia, but this will be my first international trip built mainly around driving (plenty of domestic road trips here in Canada though). Never been to this region or Africa in general, but my primary interests are wildlife, nature, and history.

The main advice I'm looking for is whether this looks too packed, or whether I'm missing some good locations/sites/attractions.

SA = South Africa, N = Namibia

Day 1 (SA): Land in Johannesburg early morning, take train to Pretoria, see historic sites

Day 2 (SA): Full day safari in Pilanesberg National Park (hotel pick-up)

Day 3 (SA-N): Go back to Johannesburg airport, catch flight to Windhoek, rent car at Windhoek airport, get supplies at grocery store, stay overnight at lodge south of city

Day 4 (N): Drive to Keetsmanshoop and see the Quiver Forest, spend night in Keetmanshoop

Day 5 (N): Go to the Fish River Canyon and do a hike or two, then drive to Luderitz and spend the night there

Day 6 (N): Explore Luderitz and Kolsmanskop, then drive to Sesriem and spend the night there (probably camp)

Day 7 (N): Full day to explore Sossusvlei and Deadvlei, camp overnight in Sesriem again

Day 8 (N): Spend morning doing more exploration nearby or set off early for Swakopmund, depending on feeling. Spend the night in Swakopmund and restock on supplies at a grocery store

Day 9 (N): Drive up the Skeleton Coast to Cape Cross, then east to end the day in Omaruru. If time permits, stop at Spitzkoppe mountain on the way for some sightseeing and a quick hike

Day 10 (N): Drive from Omaruru into Etosha National Park for self-drive game viewing. Spend night camping in the park

Day 11 (N): Full day in Etosha wildlife watching, camp overnight

Day 12 (N): Spend morning in Etosha, then drive to Windhoek and stay the night

Day 13 (N-SA): Return rental car at Windhoek airport and fly to Cape Town. In Cape Town take public transit or uber to hotel and check out waterfront

Day 14-16 (SA): Three full days in Cape Town. Depending on weather forecast and tour availability plan to hike Table Mountain, do one or more scuba dives, and go on a wine tour

Day 17 (SA): Rent a car and drive down the Cape Peninsula, see Boulders Beach, and end the day in Hermanus

Day 18 (SA): Drive to Mossel Bay and see the Dias Museum

Day 19 (SA): Drive to Knysna. Along the way stop in Wilderness for some hiking and at Dolphin Bay for whale watching

Day 20 (SA): Drive to Plettenberg Bay. Hike and explore beaches along the way

Day 21 (SA): Drive to Addo Elephant Park, explore looking for wildlife, and camp for the night

Day 22 (SA): Drive to East London, stop at some beaches along the way, see the museum, and spend the night in East London

Day 23 (SA): Return rental car, fly to Johannesburg, and then catch connecting flight home