So if anyone wants a strategy to beat the chapter 3 boss here you go.
First and foremost do not try to melee her, you'll probably get grabbed and lose half of your health and she'll heal the same amount. Only melee here if she charges, dodge it, then back off after a few hits. Only shoot her with your basic gun until the adds show up. Once they do focus on them until you get three or four circles at the bottom of the screen, afterwards find the boss and hit her with the long ranged Burst. This will do a lot of damage to her but note that the long range burst does have knockback so don't be surprised if you snap onto another enemy. Repeat as needed and she should go down before everything else does, and afterwards it's just an easy clean up.
If you're hurt you can use the close ranged charge attack to steal health from any enemy that has a heart under it, while also getting burst stacks. It's better to do this versus finishing off an add since you can get more stacks that way.