The population of a country is not always a headache for a state rather it will give huge benefits. let's take the example of China, it's the most populated country in the world but still, its economy is stable not only stable but is in competition with the superpowers. The more the population the more will be the economic strength. This shows that population does not negatively affect a country's poverty.
China is an example of a country that planned ahead for its population growth. They’ve got a strong economy simply cause they manufacture and export more than they import. Being trade partners with lots of countries, there is no shortage in demand for these goods.
There are lots of examples of countries having a considerable high population but poor economy with a low standard of living for most of its citizens. The more the population, the more the economic strength is wishful thinking as a growth in population in a country would overwhelm any government that fails to envisage and plan for the population growth.
as long as you can utilize the excess population, this can be used as a force to develop a country's economy, but it is not easy to coordinate the excess number of human resources, because if it is wrong, it will only result in an increase in the number of poverty rates, therefore infrastructure, Natural resources, human resources and other supporting facilities are the strength to create a country with a strong economy
A well educated country with sizeable population would have a high purchasing power consequently the economy of that country would improve, China with their huge population had well utilized it, they have a large strength of military personnel which is a very big advantage, in technology many of their youths are trained to build and assembled electronic, electrical gadgets and other equipment and so on, though the country has put on policy to control their population yet the existing policies is developing the country, however countries where there is overpopulation especially in some African countries unfortunately hadn't utilize that opportunity due to high level of corruption by their rulers.