I suggest using:
3 Amber Archon Shards with casting speed.
2 Azure Archon Shards with armor.

1. Press 2 on enemy hotspots.
2. Press 1 (will make enemies take ALOT of damage when using weapons etc. in the bubbles, basically lighting them up as a Christmas tree with numbers)
3. Fire primary then secondary weapons inside the bubbles (this is where [Synth Reflex] comes in), Breach Surge will deal ALOT of damage every time the enemies get hit.
4. Profit?

Press 3 or 4 to regain tons of overshield.

Umbral Vitality or Rolling Guard

Primary weapons for this could be: Secura Penta/[Penta] (DO NOT DETONATE, the grenades will bounce around "forever" in Magnetize if not detonated, hitting the enemies over and over) [Nataruk] or [Torid] (with armor stripping build). The [Nataruk] seems AMAZING to be honest, when it works, it seems to be unreliable from my testing.
Builds:
Mag Breach Proc Maker
Naturak Build

Secondary weapons for this could be Mara Detron/[Tenet Detron] with [Seeker]. the projectiles will fly around in Magnetize and pierce the enemies multiple times for amazing damage (especially with [Wisp] ability) build: Mag Bubble PEW PEW

Could also use Gloom for amazing slowdown in large area. (even though the bubble will pull enemies in slower, I still thinks its worth it in case you are in a bad position ETC.)

Breach = AMAZING DPS (but would only suggest if you don't play solo)
Gloom = Basically invincibility (would fast [Reach] 95% slowdown with Molt Augmented)

COMPANION:
MOA companion with [Calculated Redirection] + [Reinforced Bond] for 60% fire rate, also [Tenacious Bond] for 1,2x critical multiplier if you use [Vulklok] weapon with a critical chance mod. The parts are: Drex Core, [Lambeo Moa], Hona Bracket, Harpen Gyro

Enjoy!

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