I reckon when the time comes then a southbound bus lane should be added to the Tyne Bridge, extended from the bus-only slip from the Swan House roundabout (which is likely set for major reconfiguration in future anyway), then Gateshead need to sort some bus priority measures for getting buses from the Tyne Bridge up into the interchange.
The “mega-junction” on the Gateshead side needs seriously simplifying anyway as it takes up too much land and currently causes a huge barrier between the town and Quays.
Having southbound buses heading over the Tyne Bridge could also accommodate bus stops to service the new arena & proposed Gateshead Quays Station which would both only be a few mins walk away.