I have tried unsuccessfully to create a mod in the style of new orders for generals as I wanted to simulate a style of warfare with consequences for the civilian population.
If someone wants to do it (I don't have enough knowledge) it would be great to roleplay and also to reflect the genocidal effects on the population that the war had in the Victorian era.

I imagine an attack order that includes war crimes that, if the front advance is successful, generates a decrease of between 2 or 5% in the population of the occupied state. This could not come for free and would have to have an effect on the attacking country: increase infamy and worsen relations with other countries. It would also have to radicalize some pops from the attacking country: the unionists and perhaps also the intelligentsia for their liberal and cosmopolitan ideology. If you can do it, it would also be interesting to radicalize, in case you have it, your own pops from the same culture that is being the victim of these war crimes.

Another option to focus the mod would be, instead of doing it from general orders, to do it from general traits. Perhaps it would be a dynamic with less impact, but if a general has the genocidal trait (for example) it would imply that he does not stop the irrational acts against the civilian population of his battalions, and this would have an effect on the degradation of state buildings and the decrease of the civilian population.