The achievement this time does not require that you avoid all dodgable attacks, meaning you can just tank the Goldor Rush mechanic, and eat the attacks. I did this by dodging the quake and initial line AOE then popping diamondback to just eat all the rest of the attacks. Being on healer mimicry you can pom cure yourself back up once diamondback expires and continue on with the fight. You'll have some vuln stacks, which might mean some extra healing after that phase, but you'll still get the trophy to get the umbrella.