With this kind of damage you’d be able to reach floor 2000 or higher in my experience. Mobs at floors under 1000 only have a few billion hp at most. Some 10B but piece of cake. It looks like even more than my Orbs damage.
Even 1000 floors above that, around 100B+ HP or more but still not quite 1 trillion. Remember the Frozen explosion multiplication is more as each enemy dies too. So you will see even more damage, possibly into quadrillions. Brutal for deadly strike crits, as much frostbiting % , GC, Barbarian, etc.
Oh and if you can, add epiphany set legend to inceease crits further for extra Brutal damage. Epiphany Gauntlet or Ring for the set, whilst keeping mashocism.
To go further, having crushing blow with your twister hit frequency will help.
For talent, replace Barrier with Sorcery on Robe and see if it affects Frozen damage. Or use focus 50% WD. I’d replace Wizardry with Amplify 40% DMG to test as well. Empower Talent is fine over Fester. Ring, use magnify for AoE frozen + twister. Add legend aoe range affix. More aoe, more frozen damage potential.
Edit: nvm I see you mentioned adding an Epiphany ring anyway. 350% crit x3= 1050% with brutal. But 437.5%x3= 1312.5% Brutal when under deadly strikes.
As for Momentum, you’d want to add adventurer or some form of Move Speed. Draught Mythic, Synergy mythic + tome or Adventurer set , and a proc like Sprint. How about a Permafrost pet, or Demonic set pet.
Won’t need many 5000+ ED but no harm in keeping it either since its basically complete.
One other suggestion is Haunting Ring with Haunting Bonus. 2x 25% Clearcast for an extra 100% dmg.
I might have said 50% Push the Limit for 50% more Mh and Oh damage but it doesn’t seem to be needed here. Only spells get affected and not every frozen explosion. Just the first.
Nova Explosion mythic, now its been a long time since I’ve seen this one. Underrated af. Btw, you won’t need 2x 30% elemental crit but 1 or 2x, doesn’t matter. Free slot for some 2x +10 Twister , or 1x because +6 all skills on Nadroji amulet.
Nice eternal Nadroji. Just no Empyrean or sanctuary on eternal legend.
Energy resource Mythic is good but discordance Twister or Bloodmagic is another choice. Energy keep .
Start combing with another element if possible with Hireling or utilising those Mirror Images and offhand. Fire for crushing flames, shock for extra debuff dmg or high voltage 100%, or poisons dot dmg. Arcane with arcanist+ascendant.