Oh, it's definitely working. It's just that she has a passive which activates when her health dips below a certain point and cuts incoming damage by 40%. To finish her, you need much stronger damage dealers. I'm in the same boat.
I know it works but I'm talking about the big damage numbers instead of doing 2 or 3k per hit with the mod I do 400k for solo raids so if they have anything that decreases your damage or increases your damage it won't do 400k but instead do 3 or 2k