I can't do it.

I'm usually spamming actions, looking at the health bars, then boss drops an aoe on me and either i don't see it come at all or i get out just a bit late and eat it to the face.

I can't seem to get copperbell hard done because of that. Biggy, the 2nd boss, has a line aoe with no ground warning. I don't even know what his Wind up looks like and i've died there multiple times, killing the party.