can't decide on a tech build

Cryobeam, Incinerate and Flamethrower all fall in the tech category, right? Could try one, or more, of those in a profile along with energy drain and/or overload to maximize combos.

I found an infiltrator build with cloak, remnant VI, and assault turret to be the most fun with the bio-converter/life support combo to never have to reload; using the isharay or dhan shotgun. It made the game easy even on insanity so I intentionally made the game harder by taking cloak duration boosts instead of damage ones and wearing crappy armor that looked slimmer than the later upgrades.

The assault turret isn't meant to do much damage (on this difficulty especially), but rather to freeze enemies with cryo ammo and recharge your tech powers faster with the appropriate upgrade when in proximity. Besides being fodder, your drones can heal you through life support by using their targetting feature.

Honestly, I go for a combo heavy sentinel build, with Energy Drain, Incinerate and Throw, but you could quite easily substitute another tech power for throw and drop the biotics for a purer tech build.

I've been toying with the idea of having a Cryo Beam/Incinerate/Energy Drain Engineer, that would combo all day every day. Cryo beam to freeze and weaken armor, incinerate to combo the cryo and apply burning damage, then ED to burst the flames. Could be quite nasty on Fiends and the like. Not to mention the combat drone at least primes for a tech burst similar to how Overload can (not sure if it detonates, though)

Elemental Wizard FTW!

Energy Drain, Incinerate, Shock Wave. All specced to detonate as well as prime.

Run with Explorer profile, and maximize every passive till you reach level 6. At some point you'll have to level another biotic skill to reach level 6 though. In the combat tree you only take passives.

Though I guess you wanna use the VI or Turret

So tonight I tried changing it up again and found a really fun build: remnant vi, assault turret, and cryo beam. I set the vi to close range/tank and detonating missiles, assault turret to cryo ammo, and cryo beam to snap freeze. The turret freezes, and either I get cryo detonations from the vi, or I gun down the frozen target for a snap freeze explosion (chaining snap freeze combos is awesome btw).
Also using cryo gauntlet and the leg augment for adding cold damage to jump melee.

Cryomancer or space Elsa? Lol

Across most of Voeld and Havarl I was using an engineer profile with Energy Drain, Incinerate, and the VI, armed with a Cryo Gauntlet. ED and Incinerate were both specced as both primers and detonators, so between them, the gauntlet, and the little defensive drone, there were plenty of combos going off.

Eventually I dropped the VI because it wasn't doing much damage, didn't really distract the enemies at all, and had a habit of wandering off on its own to start fights with enemies half way across the map without my input; but ED + Incinerate + Cryo Gauntlet were with me throughout Heleus, chaining combos off each other.

Here's my usual plug for Energy Drain over Overload.  

Overload, on it's own, is a much better shield stripper than Energy Drain, plus it's got the ability to chain between targets.  Has a pretty useful momentary stun too.  It's a great power, and one I certainly wouldn't dismiss.

However, Energy Drain sets up tech combos more easily than Overload (you hafta be real quick to detonate an Overload prime, it doesn't last long) and a tech combo strips most, if not all, of the shields from a "standard" shielded enemy like a sharpshooter or one of the mini-gun Kett, and this is on Insanity.  If the shields aren't completely removed by the combo, a very short burst from just about any weapon finishes the job very nicely.

Energy Drain has added utility over Overload, in that it refills a significant portion of your shields, and a tech combo off of it leaves a very nice electric field on the ground that works as an AOE stun.  I've caught quite a few mooks in that field, leaving them VERY vulnerable to weapon fire, or further combos.  Energy drain is one of the few powers that is dual purpose, meaning it detonates combos (and with the right evolutions) primes for combos as well.  

It is my firm belief that unless you're not building your pathfinder for combos, Energy Drain is just overall more useful, even if Overload is better at the shield removal role.

For a while I ran an all electric build using energy drain to prime and then chain overload to detonate.

My set up
1st badass spec: both constructs with priming and Energy drain. Also you need a weapon with technical rounds and the aug where mid-air you fire 30% faster, i chose ghost. it meelts. fun build and absolute mayhem since there are 5 people in your party. Robotic fusion is advised for maximum battlefield dissaray
2 profile: incinerate, overlod and energy drain.
3 and 4 profiles : cloak with energy drain and ceyo beam or Flamethrower respectively.