Build essentials :
Ties That Bind - No need for an explanation here
Stillness of Mind - Essential for survivability, as this build is not very tanky
Terror Anointments - Apply Terror after AS end. Terror anointment on Maggie to limit accuracy and handling penalty from Terror mechanic. Ammo regen greatly improves the flow of your gameplay and damage output (less reloading, more shooting).
Magazine increase Artifact - Without it the ammo regen will be much worse.
Dread - Damage buff and Weapon reload after killing Grasped enemy.
Sustainment - Main source of healing. Will only heal you when you shoot a Grasped enemy. Doesnt work on non elemental weapons even with Infusion.
Overkill - This Guardian Rank perk can greatly improve your damage output. During this Halloween event the Ghosts will make you waste your overkill damage though.
Phasezerker Class Mod - Maybe not essential, but it does provide pretty big damage bonus, including Do Harm interaction with Ties That Bind, where it will increase damage done to Phasegrasped enemies.
Situatuinal Awareness - The build does not have much healing outside of Sustainment + Ties that Bind combo, so be aware of your surroundings and keep an eye on the minimap.
The Build
Quite a few things in the skill tree are not essential, so play around with it, experiment.
Video with some Slaughter Shaft gameplay. Round 2 Neutral’ish modifiers and gear can be seen at the start of the video. Build is at the end.