I despise anyone who becomes a soldier of their own free will. The moment you enlist, you accept that you will be obliged to kill, and that you will have no control over whether that killing will be justified.

I wonder what would happen if we didn’t have a military at all

Thats the trick. If a country doesn’t have a military and they have something like resources other countries want. The become puppets of the countries that have militaries. The exceptions are small countries that don’t have enough of anything anyone wants for others to bother taking it. They don’t tend to do so well usually.

It’s a race to the bottom.