https://pobb.in/gBYOw0ldJouj

Thought it would be nice to theorycraft a bit with hiero. Turns out between kugals gaze, new bubonic trail and the hiero ascendancy and a mana mastery, you gain 100% (150 if 1k mana spend recently) arcane surge efficiency which equals 40% more damage with new hiero. On top of that, you gain 25% RMR from hiero, 24% from bubonic and 12% from new mana mastery. If you take souvereignity on top, you're at 83% global RMR that applies to every aura. This build runs 2 heralds and 3 50% auras.

This uses reworked tulfall as a (possibly) cheap stat stick, minimum power charge rings+willclash+malachais loop to have permanent 8 power charges and 40% spell block from willclash, or 74% spellblock in total.

I was to lazy to fully make some gear e.g. the gloves are too good (should just use hrimsorrow and get another mastery tbh) and arent actually achievable but the rest should be pretty cheap if bubonic doesnt spike in rarity. Didnt put much thought into spell mitigation probably would require some additional thinking but theres certainly more options here than for phys mitigation.

In endgame you want to get more power charges with a corrupted willclash and void battery and get minimum charges via grand spectrum jewels.