That's the purpose of basic training already, but we don't want soldiers with no empathy. Soldiers are far too valuable to turn them into rage monsters, we need team players who will actually save each other if they're hurt and won't randomly attack civilians.

IMO we're also pretty close to being able to have robotic infantry drones, which are going to make enhanced human infantry kind of moot anyway. Imagine if you could take something like the Boston Dynamics ATLAS robot, stick a gun on it and paradrop it into enemy territory. It might need to be a bit lighter and more agile, but we're not that far off. It doesn't even necessarily need AI, you could remote-control the thing.

Robots need to be faster, lighter, more agile and with longer battery.