I hit 21 finishing off the demon in the pit in the final red fen quest. Up until that point the combination of acid rune arm and epic double crossbow worked.
Then comes red named bosses and things were not entirely up to code. The issue with the combo isn’t lack of okay DPS, it’s that arti’s don’t have that one thing. The big nuke. The sustained nuke. But they do have basic cc (tactical detonation), maybe a half okay boom (acid energy burst – twisted) and an array of simple things.
Heck, even PK works (Gnome iconic race feature) as long as you don’t run EE. And okay that it works situationally. In fact in combo with double crossbows neg level ability PK can go off more than enough. And if you manage to fit an okay illusion item into the mix you might even be half okay with it.
On EH it’s one of those 60-70 percent chance which is good enough.