Finally killed it. Everybody is using Crown + MAnchor for this, but my pow was just way too low with Crown (1.708M) and MMast increased it by 40k so I was doing more dmg with her, but damn this fight is kinda tough when you have no shields and no one taunting with invul.
All the laser shots went to RRH and they kill in 2 hits and break cover in 2 hits as well so I had to make sure to time Helm's burst in a way so that RRH could heal back to full for 3 of them and then let the last one hit cover since you need the cover later on when the laser shots happen a second time one can be tanked and the other hits cover and then you can burst with Helm again to tank the remaining two
Half my team including RRH couldn't survive the second AoE attack so I had to kill the boss before that one and you gotta burst pretty fast throughout the whole fight to get the last RRH burst off to kill the boss