How to Unclok Engineer
I can confirm that Engineer does exist. I found my version of the Engram for it in The Aeon Vault in the second half of N’Erud. But I believe it can also be found in the Timeless Horizon, the 2nd tileset/region that the game chooses between it and The Aeon Vault.
From where I found my version, you need to skim around the top/north and north/west top/west of the map. Stay close enough to where you get the instant-death buildup for going too far, and keep going/skimming the map border until you find the rock formation that looks identical to this one.
Note, this is if you have The Aeon Vault which is where I found my version of the Engineer Engram. I don’t know where specifically/direction-wise it would be in the other tileset that would be chosen by the game over The Aeon Vault so you’ll need to do some digging of your own. Hope it helps.