You’re probably going to need some form of cc(stuns,freezes,etc) or surivability(perma stealth) or pretty much high high high high damage. My current builds, or spells, even Aftermath meteors can barely survive, i have higher survivability using twisters, because of their cc, which was how i got my eternalized/crystalline weap/hat.
The 100% element damage(ed) is the red legendary affix, which can only be obtained through dropped items, such as Mutiny, Insolence, Aether Cover, Aether wrap, Crystalline weapon, Cognition, Entropic Jewel, Apex of Epiphany, Loop of Epiphany, etc. They cannot be obtained via crystals. You can read more about Affixes that cannot be obtained via crystals in Crystal Crafting Restrictions
But yeah, think about maybe incorporating something that has cc, or perma stealth, or high damage and go from there.