I don't know what it is with the JNB route and Virgin's 789s.
I've flown to/from LAX multiple times on the 789 and A350 and not had an issue looking out of the windows .... from my window seat!
But JNB, its arrives at something like 11:30am local yet the sodding window shades are inoperable until 40 minutes to landing .... not only do you miss the lovely African sunrise but also your body is fooled its dark when its been daylight outside for several hours to landing, and there's barely any time difference to LHR.
I took my family on this route earlier this year, their first time on Virgin. Loved the Clubhouse, the PE seat and cabin and cabin crew, all good. But really really annoyed at not being able to look out of the windows; they were far too polite to ask on board.
I've yet to find a sensible answer and empathise totally with OP Paxing.
It's a bit like the BA puzzle that was the disabling of the A380 Club World screens, for a while; but at least BA listened and sorted it.