Primordial Dweller NM
Found a few videos and I think we are doing everything correctly, just need to execute. They hinder the exploding adds or DPS them as needed. The one guy uses whiteout manifestation which I can run if I'm on DPS. On one video, they 4 man him and that guy is running the pistol cleanser on CD so I assume there is some debuff being placed on the tank? It sounds like they also purge something on the boss. On the 4 man, they are all 4500 HP or more. The 5 man, they aren't but their DPS seems to be really high.
I don't recall seeing any kind of debuff on me. Also, me dying was never the issue.. I was very rarely below 80%.
More health could be a solution, certainly enough to survive one of those blasts. However, it can certainly be done with 2k health as long as things are executed perfectly.
I think our biggest issue was letting the bombs sneak up on us. I think people are forgetting that they don't have to watch the boss to DPS it.