You would be correct to say that less fentanyl trafficking and less human smuggling does reduce violence and human suffering in the world.
Discussion
The narco wars are another problem created by state regulation. Until you see that government caused the problem you have by "fixing" another problem, will continue to think of government as a solution.
You would also be correct to say that governments allowing unchecked illegal immigration and unenforced border laws is the primary source of income for violent cartels and gangs.