WI no Virunga volcanoes?

[Straha]

OTL, Lake Tanganyika drained north through Lake Kivu and along the
Rift Valley into the Albert Nile, until a few million years BC the
Virumga Volcanoes arose and blocked its course in western Rwanda, and
the water diverted into Zaire. If there were no Virunga Volcanoes,
the Nile would now be much longer than the Amazon, and bigger than
the OTL Nile, and its longest headwater would rise in northern
Zambia. That would mean (1) it could irrigate more land, and (2)
penetration of central Africa by boat would be much easier. (And
perhaps also no mountain gorilla apes.)

[wkwillis]

I think the Sudd is the key to stopping travel and commerce on the Nile. It's a big swamp that retains water to even out the Nile's flow, but it stops commerce dead.
If the Nile was twice as long and went to the Katanga copperbelt it would be a major source of copper for the world market. Cyprus would no longer be so important for control of the Mediterranean before the discovery of iron. Is there tin in Rwanda/Burundi/Uganda without the volcanos?