Just to double up on Ian's post, I have moved my second account to Colonia. He had only one Odyssey engineer unlocked in the Bubble, and not many materials to begin with.
After the latest update I started using him more, to see how the unlocks worked, with the new mission rewards and reduced material requirements.
In about a week of just doing missions (which I enjoy), I managed to unlock all 4 engineers and get materials to modify 3 suits to G5 and a few weapons.
The caveat, however, is that I have been playing Odyssey for a while so, even with an undergeared character, I know how to handle some tricky situations, which might not be necessarily true for a player who approaches them for the first time.
The trip to Colonia can be quite an undertaking, but it pays back, in terms of "time to engineering"