Graviton Vortex is indeed for crowd control and is meant to be paired with a sword charge, particularly something from the brandish line. You can use it to kill jellies or gremlins, but compared to something like a Gran Faust or Acheron it is a bit slow.
You might start a new thread that lists your armament and goals then asks for recommendations. Without a lot more context it is difficult to give advise.
i am going to get a weapon to do every kind of damage and i noticed that the graviton vortex is the only bomb that does shadow and i have heard that it doesn't do much damage so should i get a sword or gun that does shadow and if so which one