Also I have a build that uses both fire and shock. It uses the shock+bleed concept as well fast dot ticking from fire+immolate+Blistering bleed .
The build below is Aftermath build for that concept but any build can work with it tbh. Orb builds , twister builds, any build as long as you can stun for high voltage, fire attacks to bleed , stack Debuff and many more. Arcanist + ascendant can be an option too.
Pure Fire Build:
Mind you he used high hit frequency orb combined with immolate+bleed+cosmic orb+ Billions of DMG to do well against enemies at floor 1400s and WITHOUT Crushing Blow!
My Seasonal Maidens’ could definitely do well at that and it does so much more DMG than cronos Devilpillar could ever do as a wizard for pure fire mode but spam orbs definitely help. For my Build, the Fire mode is called Wildfire Summer Maiden and this just means replacing Frozen set with Inferno and Pathfinder with Vampiric Touch. Either Vampiric Touch pet or Inferno pet.
In the end, it’s about high hit frequency, high DMG, great use of shock DMG like stack Debuff+ High Voltage and bleed for high floor.
Crushing blow for high floors when you reach a point where ever your own DMG isn’t enough for super high floor (and for ease of killing).