Congratulations!
Tank damage in the fight isn't really a big deal; there are a few tankbusters but you can invuln cheese many of them and the others are pretty basic cooldown+shield=np. The raid-wide damage can be more of a thing, and it's the first fight I can think of that actually makes aggro management a group effort. Tanks need to be smart about grabbing threat, healers need to be smart about controlling theirs, DPS need to minimize their screwing up and keep an eye on their threat since aggro reset.
I don't think it's particularly hard hard, and the difficulty should curve well with gear, but I do think most of the work that exists ends up on tanks and healers. We've been trailing RDMs and we're able to take some guy who'd only been like a minute into Exdeath into 4S and hit enrage in like two pulls and then clear him a few pulls later because most of the pain points of the fight don't involve DPS doing things so much as DPS just not dying (which is still important! but is easier to pick up via reaction, while the tank and healer stuff generally needs some preplanning to allocate CDs).
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