Eidolon [Zenith] unfortunately requires a riven, all you need though is critical damage and multishot to make it viable. Do your best to get a harmless negative to boost the stats, and if you’re going to get a third positive have it either be fire rate, electricity, or damage.

Deadhead recommended for weapon arcane, it's just not there for the sake of showing the damage numbers on overframe 'realistically' speaking. (Don't trust overframe's damage numbers.)