This build is for Toxin Progenitor, doesn't seem to be implemented for codas yet.

Arcanes

Encumber is very comfortable, self priming and has similar dps to Deadhead. Outburst is highest dps with nearly any amount of priming, though less comfortable.
If priming (even just through companions), do not use Encumber, use Outburst or Deadhead

Mod alternatives

[Primed Pistol Gambit] can be changed for [Galvanized Crosshairs], note that the stack system is truly horrible and is a significant drop in Quality of Life

Alt modding route

Pure corro gives a lot of slots to play with, combined with enemies being made of wet toilet paper this build scales fine if you have basically any buffs or enemy debuffs. If you don't care for punch through, specifically want to kill single targets or don't plan on buffing your weapon whatsoever: https://overframe.gg/build/816612/

Rivens

Despite being minimum disposition, rivens aren't the worst idea. Mandatory stat is Punch Through (toxin for the single target variant)
Other good stats are crit damage/multishot/fire rate/crit chance
Riven slots over [Merciless Gunfight] with Punch Through on Riven or [Pathogen Rounds] with Toxin on Riven
Once disposition increases a bit more, a riven with Multishot and Fire Rate will be slottable over Lethal Torrent (optimal would be CD/MS/FR -Harmless)
OR with Toxin and Fire Rate, can go over [Accelerated Isotope] and switch Progenitor to Magnetic