Do we even know if the MC has committed war crimes ?
IIRC Akira said a mission/operation the higher ups want to keep under the rug, so this wasn't only about the MC.
Blackmailing a soldier as done by her is a bit nonsensical. Even if the military or public wants to put the blame/responsibility on someone, it would need to be a commanding officer, someone which had authority over said operation. Puting all the blame on a normal soldier for an entire opration isn't going to work well.
Than there is also the point, if this really was a spec ops or black ops operation, there is no way Akira would get away with revealing military/state top secret information and persons involved...having a rich, influental father is not going to change that, thats's a long prison sentence at best or an unfortunate accident.