On a side note, one mission I actually love - Exodus - is also one of the most frustrating.
Because I make it a point to save the Nebtuu.
The first 40 seconds of the mission require incredibly precise actions and a bit of luck when that first Seraphim wing jumps in.
1: Target the moloch's beam turret, fire trebs at it.
2: Call in Theta Wing reinforcements
3: target each individual Nahema next to it, fire trebs at each.
4: Turn to take out the Seraphims jumping in
5: kill the 3 Seraphims before they launch bombs because of their invulnerability preventing you from intercepting them until they hit the Nebtuu. (besides, you'll kill the Nebtuu yourself with your Kaysers if you try...)
6: Get Theta to protect the Nebtuu for the rest of the mission.
7: Wipe out the next 2 Nahema wings really fast because they also target it.
If you did all that, THEN it'll survive because
didn't expect anyone to do that and no enemy will target it anymore
And it's obvious
expected the Nebtuu to die because there isn't a bonus objective for saving it.
But I make a point to do it each time