However, if uncontrolled population growth will lead to poverty and unemployment, excessive exploitation of natural resources, overcrowded cities, pollution and so on.
but it all depends on the government because it's not an easy job for them but they have to be able to handle it from top to bottom.
I kind of agree with your line of thought, a high population if properly harnessed Will automatically lead to high productivity and efficiency.
Take a very good look at China, they are over a billion people, but they've been able to manage their economy properly, reducing crime and poverty, they one of the richest countries in the world with a high productive workforce.
There is hardly a country you will go today without seeing a Chinese company operating there. So population growth at some point is advantageous
On the other hand, population growth can be dangerous if not properly handled, like you rightly put it can lead to serious unemployment and poverty. Nations like that have a high percentage of crime rates and unproductive.