Thank you for the detailed response. Yea thorns is doing some weird shit and making you take damage with zerk. Super odd.
How did you kill t5 p8 heralds on zerk without getting 1shot?
Part of being efficient is spawning weak heralds, ideally minion types. Rakanishus, skeles, ... these you can tank easily and kill fast
Stronger t5 with bad affixes take longer, use war cry to stunlock and land hits between refresh. They will chunk you but never been close to being 1shotted, 50% pdr maxblock. The harder ones can require a full belt of rejuvs, just stock up while farming tokens. Requires more work but that's the price you pay to play shit tier pvm chars