Assisting during disasters

Emergency responders do this with much less overhead - like, well, weapons. They also receive a much more extensive training for this specific kind of thing.

Stabilizing areas

UN Peacekeepers do this. National armies serve “national interests”, as defined by the government backing them. They are not always interested in deescalation of conflicts, and US Army is particular stirred so many conflicts and made them worse because it served US government.

It’s not the soldiers decision

It’s their decision to join the army and voluntarily give up their right to refuse. If you know you can be sent to raze territories and people, why do you join in the first place? There are better places to do good aspects of what army does.

The primary role of military is to project power by either destroying or threatening to destroy anything a given government doesn’t like. Everything else comes secondary, and if not for that, we would have dedicated personnel only meant to do the good things instead. Don’t buy weapons and helicopters, train people to respond to emergencies and assist local civilians in hostile areas. UN does this. But hey, how do you instate banana republics then?