If you enjoy spamming 1 on [Nidus] but feel like you do no damage this build is for you.
With [Abundant Mutation]'s you can now stack to 300 stacks and you will do enough damage to solo steel path survival.
4 is replaced with [Ember]'s Fire Blast ability for stripping armor but you wont need this for the first 45+ minutes of a steel path survival mission.
[Adaptation] can stay rank 0 but putting a Umbra forma on [Nidus] is worth and will allow you to upgrade [Adaptation] to build resistance faster.
The aura can be replaced with anything you want, I chose [Steel Charge] for the extra mod capacity but if you have a Umbra forma this is irrelevant.
Weapons do not matter as this is an ability focused build but using any of the Syndicate weapons is encouraged as they occasionally heal you or give you energy (which is never needed but could be nice if you somehow messed up your energy).
For playstyle simply keep your 3 up at all times, use 2 to grab a pack of enemies, use 4 to strip their armor (skip this untill you really have to) then spam 1 untill you can use 2 again and repeat.