Why this build over arbitration build?

This build by sacrificing some duration, allows gara to have some decent cc through the use of her 3 and 4, nuke anything up to about level 60-80ish or so, and if you still want her 2 to be the main focus it can be but now it has more range to kill enemies.

How to use the abilities?

Shatter lash: you will mainly use this ability to do a quick small nuke around [Gara] or more importantly break her 4 to scale up her 2 and at the same time nuke the map.

Splinter Storm: Splinter storm is meant to give [Gara] Damage Reduction, later in the mission it will become the main focus of damage as you can walk up to enemies and they will die.

Spectrorage: [Gara] wants to use this in a large group of enemies due to the augment ([Spectrosiphon]) which gives energy to [Gara] and her team mates, it also has some small cc use to distract enemies for a second or two.

Mass Vitrify: Her glass wall is meant to due 2 things, either nuke the map in modes like def, mobile def or intercept, or you can use in combination with her 1 to scale up her 2. (note that her 4 refreshes her 2's duration removing the need to recast her 2)

Arcanes

Arcane energize: this in combination with her 3's augment is really overpowered highly recommend if you have it, although it is not need for the frame to survive on energy as you still have zenurik dash and energy orbs from her 3.

Arcane Grace/[Guardian]: Grace and [Guardian] help with survivability since we dont run [Adaptation] on this build, again arcanes arent needed like with some other frames but it really helps if you do have one.

Mods

[Cunning Drift]: This mod can be replaced with [Power Drift] for more nuke potential and faster stacking of her 2.

[Corrosive Projection]: This can be replaced for a lot of things, [Brief Respite] for more survivability, [Energy Siphon] for more passive energy gain, honestly go crazy with the aura slot here.

Everything else is pretty much my own choices to a balanced build, just take the concept of using [Spectrosiphon] to give energy to allies if you want to go full umbral go ahead or you want to replace cunning go ahead this build is semi flexible.

What modes does is work in?

This build works in practically most modes albeit railjack, hijack, capture as those modes don't really need enemies to be killed often if at all and [Gara] wont have as much of a use in besides fashion frame.

Concluding Thoughts

Overall, I really like this [Gara] build compared to the normal 300+ dur build that aims to keep things alive as it does allow her to have a more "active" playstyle if you know what that means.