Almost on principle, I would say that peace is always better than war.
In the case of Argentina, my country was neutral in both world wars
I would not know if it was for good or for bad, I am not a specialist in those subjects.
What I do know is that, after 1945, the United States privileged the relationship with Brazil (which did declare war on the Axis and even sent regiments to Europe) as an interlocutor in South America, strengthening its armed forces and privileging its investments.
Was it better for Brazil? Worse for Argentina?
I do not know, but it was one of the factors that changed the South American geopolitics.
Excellent question Dr. Gustavo Chalier. I think Argentina was disadvantaged by neutrality in World War II. Portugal already, I don't understand the reasons of neutrality. Maybe Dr Carlos can explain us better.