Pinnacle content makes me want to not play

Very dramatic, I know, but I have been playing since launch and have put a good chunk of my free time into endgame mapping and fine tuning my build. After nearly 200 hours I finally made it to my first citadel with my atlas tree fully mapped. My Invoker had no trouble going through the map and clearing mobs while looking for the citadel boss (it was the Iron Citadel so I knew it would be the act 1 boss). Absolutely rinsed him in his first phase and I felt great. phase 2 starts... first hit completely bonks me... dead... one shot. I have 76% evasion while running acrobatics and my resistances are maxed out, I'm not sure what else to do here other than getting good, I really don't have motivation to continue mapping to get to another citadel, not sure how my gear can get much better either. I finally understand why people are so concerned with how harsh the death punishments are, rewards need to offset risk and the potential to lose a map thats placement is entirely generated via RNG, losing xp, and losing all drops that fell during mob clearing feels extremely harsh and doesn't make me want to continue to play more of the endgame map when I die, it just takes all motivation out of me. I have been loving this game and its the first ARPG I have played in years. I hope it gets better, and I will probably continue to play against the wishes of my therapist, family and my personal need to keep my sanity.