Swen stated that any dlc they do end up making would be Before* the ending of bg3 which i honestly would agree is the better option narrative wise. Beating the BBEG and saving the city kind of loses its OOMF if your then continuing on to avernus.
Not saying we wont get to go to avernus to find a cure for karlach, i just think if they go that route it will be added in act 3 at thw latest. Similer to getting into the house of hope.
