Thinking about this further, they never actually showed Shuri die. If I recall correctly, the only evidence we had on screen that she died was a video screen showing her "missing" along with the other snapped victims. Sure she came back through the portal with T'Challa, but not everyone that came through that portal was dead, see Okoye.
So I guess it's possible that they can retcon Shuri's story in the five year gap between Infinity War and End Game, and write that she went underground/off the grid to do black ops shyt with Nakia or whatever, but was around doing shyt, and wasn't a victim of the snap.
Until we hear otherwise, I think it's possible that BP 2 is set during the five year gap before T'Challa returns.