I highly suggest you use projectile weapons with high Punch Through and decent Status.
I suggest these two:

1. Exergis

2. Felarx (My personal favorite with [Xaku])

When [Xata]'s Whisper is active and you hit an enemy (or group of enemies) if they don't die, the Void status effect will make the projectiles keep swirling inside the bubbles and kill them and every thing around.

Abilities

Cast [Xata]'s Whisper and Grasp of [Lohk] to grab up to 15 guns from your surrounding enemies (31 if you get the void 'reaction' after you crack a relic open) and cast The Vast Untime to freeze their count down. Try re-casting this ability before it ends to decrease how much the timer runs while inactive. During casting, the other ability timers start running but its just less than a second.

In addition, casting The Vast Untime will hit enemies in a large area (66+ meters) and make them 50% weaker to void damage. Thus, strengthening the damage done by the floating guns and by your weapons imbued with void damage by [Xata]'s Whisper.

Helminth Ability

Most people replace [Xaku]'s first ability, [Xata]'s Whisper, but this is my favorite ability from him (and the helminth for other frames) and it is great for the two weapons I mentioned above. After playing a couple of hours with [Xaku] I noticed I wasn't really using his 3rd ability. I know its a great one but I was just not needing it. So I changed it for Ensnare. Ensnare, [Xata]'s Whisper, and the Felarx (My personal favorite with [Xaku]) or Exergis have a great synergy since, like I mentioned before, the projectiles keep swirling in there hitting EVERYTHING.

Survivability

Xaku's ability gives him some evasiveness but in Steel Path this is almost as if its not there. Anything can 1-shot you after your shields are down. The augur set mods in this build, plus [Augur Seeker] and [Augur Pact] on your secondary will give you 200% [Energy Conversion] into shield with you cast. If you cary a Decaying Dragon key, replenishing all shields and shield gating will be easy as you can any of the abilities here (except Grasp of [Lohk] if you already have the maximum amount of guns floating).