Gotta get it down to the point where you throw dva bomb first to bait the shield and then count down from 3 and emp right as the bomb explodes for the wipe
EMP to nulify the abilities, then Zarya grav the enemy team, then use an AOE ult like Tracer's or Dva's, then Soldiers or Mei's ult just to get any survivors
best ultimate combo is Zarya + Sym beam. because you use 1 ultimate and her beam cleans up also its easy to avoid Rein/Orisa shields when you have full control, no need for EMP lol