I think developing AI for diplomacy would be a better net use of resources for humanity
they did it! https://ai.meta.com/research/cicero/diplomacy/
Many wars are the desired outcome of the leaders that started them.
Diplomacy is important, but most effective when war is also deterred by credible response.
Diplo.A.I: "Rudimentary creatures of blood and flesh, you touch my mind, fumbling in ignorance, incapable of understanding. Organic life is nothing but a genetic mutation, an accident. Your lives are measured in years and decades. You wither and die."