The two biggest populated countries of the world are China and India. Both are doing good in terms of growth with China leading and India trying to catch up. Moreover there are also cases where country is less populated like Switzerland but still one of most developed country of the world. I think population is not relevant, as long as you have plan to execute in right direction no one can stop you from going up.
Not many countries with such a large human population can catch up with what China has done. It takes advanced thinking from a leader to get their country out of the pressure of decline. China is trying to control and dominate the world economy through trade routes and the products they create and currently they almost control the Asian market. India is far behind compared to China, but they are slowly trying to implement a strategy like China, by offering products and industry to several Asian markets in particular.
Population is not very relevant which can prevent any country from getting out of economic problems, but a large population can also hinder the country's economic growth because a large population can make it difficult for the government to increase the source of income for the country. If the leader has a concept in managing the country then population size may not be very relevant which can affect the decline of the country.
A large population for some countries is a positive thing because a large population can be used as a subject for development, the economy will develop if the number of workers is large. A large population, if accompanied by adequate population quality, will be a driver for economic growth. On the other hand, a large population combined with low quality makes that population a burden on national development.
So in my opinion it doesn't have a significant negative impact on the economy in a country with a large population, it's just that the government needs to increase its quality human resources with quality education evenly and be able to master technology so that it can help the country to achieve development targets.
However, if it is mismanaged it will really make the situation worse. The large population and its high growth rate have consequences for the difficulty of finding work, high food prices, education and health costs and many social problems due to the large number of unemployed and so on.
Your reasoning is partially correct, but it ignores the complexity of current population management. A huge population doesn't guarantee a strong workforce or economy. More people don't necessarily mean more progress. Human resource quality is key, and that's the issue. It takes competent, educated people to innovate and produce, not just bodies. Don't even mention socioeconomic inequities from a mismanaged large nation. The government must “increase” quality human resources and distribute them fairly across industries. The problem of managing technical advances in a vast population is another issue. It's not enough to master technology; you must integrate it into numerous industries without furthering inequality. Thus, while your excitement about a huge population is encouraging, you must examine its many obstacles