Investigate Remnant Derelict
This follows immediately from Parlay With The Krogan. Drive the NOMAD straight into the ruined ship to kick things off.
Pick off the Raider welcoming committee, but be sure not to stray too close to the patch of Scourge tendrils- the turrets there are extremely punishing.
Instead, work your way toward the objective by using the trenches alongside the killing field.
You'll have to deal with turrets here as well, but only one at a time. Just be careful with your jumps- if your head goes above trench level, the field-turrets can fire on you.
The trenches lead you to a large room where Raiders are fighting adhi & Remnant. Play the spoiler and take them all out.
When the coast is clear, you'll need to find a glyph for the console. This is to the east, on one of the giant rills.
Go to the console (you can scan the nearby drill for research), and enter the solution (start in the center and work outward, if you're trying it on your own).
Follow the passage. Just as you get close to the next console, look right for a container.
The console activates a bridge- cross and then jump off a ramp to the north for another container.
Follow along the passage until the next console. It opens another bridge, but don't be too hasty- about halfway across some of the pillars fall away, and you're left jumping for the remainder.
Use the console at the end of the bridge.
This reveals that the drive core has already been taken. You can track its path via the red flares to the west, but first follow the ledge east for another container.
Now you can pick up the trail of the flares. Nothing ominious there- just bloodred light shining on eldritch, nightblack metal. Cozy.
Follow the trail, scanning some Observer Generators when you reach them. The Observers themselves are in the next section, along with some Breachers, and then some Assemblers through a door past that.
After that, you're in the clear, just follow the flares back out to the surface.
You'll emerge at a Forward Station site, so you can call the NOMAD for the next leg of the journey, but this quest is complete, linking directly to Search for the Stolen Remnant Core.
You do get Viability for the completion.