The real question would be how much land is used by the extremely rich versus the poor? If someone has a house of 5000 square meters, and a garden that is at least 10 times as much (and we know that the rich like to have much larger estates), then the problem is not that the land is occupied by people, but that it is unfairly distributed. For an example, just look at this article -> The world's biggest private landowners
Furthermore, there is enough food and water to feed all the inhabitants of the planet - but the rich and the less rich throw away huge amounts of food, while on the other hand almost half of the world's population does not have enough food or even dies of hunger. For example, the US is the country that throws the most food in the world (40 million tons per year) and have about 37 million (slightly less than 10% of the population) who do not have enough food (11 million children). What a paradox for the greatest democracy in the world -> Food Waste in America in 2021
This is definitely something that needs to be worked on, and it is up to the governments of those countries to pass some guidelines or even laws on birth control. But this is not easy to achieve even in countries like China, which introduced such a measure in 1979 and lasted until 2015, and it is estimated that the end result is about 400 million fewer births in that period.