Gets the job done.. and then some
This No Forma build can do anything no problem. Eidolons. Orphix. Steel Path. Profit Taker Shields.

• Shields just get in your way on mechs because they prevent [Rage] from activating consistently and in any decently strong content they're gone in a blink anyway without some kind of adaptation to work with them.

• Necramech Intensify doesn't increase guard mode damage and even if it did; the Arque already does plenty of damage

• Every forma you put into this build afterwards will basically just be to customize it with QoL improvements to your liking.

The higher jump from Necramech Hydraulics is basically necessary for mobility sake. Likewise for Nechramech Thrusters.

Necramech Augur is really fine at the lowest level to constantly shield gate and then quickly be able to take advantage of [Rage].

Storm Shroud is all you need to worry about for survival. After casting it, you will [Recover] a small amount of shield which then breaks for short invulnerability. Cast it before entering guard mode every time, then shoot until everything is dead or you almost are. (You can immediately recast Storm Shroud after exiting guard mode but not during). You have to eventually let yourself take damage to replenish energy or you'll wind up being able to cast neither Storm Shroud OR Guard Mode at which point you're as good as dead. (Though sometimes letting it die so you can respawn it with energy shortly thereafter is better than waiting on repair to proc several times in a row)

Your first forma (Repair) will let you add a rank 2 Necramech Streamline or max everything but Augur ([Streamline] would be best).
What you do from there is all preference in what you max first afterwards. You could go all mobility or add some duration/range.

Necramech Aviator seems tempting but it's redundant because you are already basically invincible. Sheer laziness is the only thing that will kill you.

The only real options for those last 3 slots after adding Necramech Streamline are Necramech Efficiency, Necramech Refuel, Drift/Friction, Continuity/[Stretch].

Have fun!