Mobile Suit Gundam: The Origin, Shingeki no Kyojin Recommendations
Space opera and dark fantasy containing a teenager who gets involved in a war as a result of losing a loved one . He eventually developes an interesting talent for war and uses it for its vengeful purposes.
It contains political conspiracy, childhood trauma, horrors of war and even some interesting military deployment . You have futuristic guns, spacecraft and mobile suits in Origin, while 3D maneuvers, chivalry and even the titans itself have same purposes in AoT.