Overpopulation is a myth. It’s one that has been alive and well for over 200 years. What we experience is forced overpopulation better known as overcrowding. In terms of resources and land there is plenty of it. There’s a 1000 square feet per person just in Texas if the whole world moved there. That’s about 30’x30′ each. While that’s of course not livable it does give you a good idea of how much land there is. The issue isn’t the population it’s how we distribute it. Fewer people are able to live away from cities or want to so we all congregate. This is known as forced overpopulation and isn’t to be confused with actual overpopulation.
You can lock one person in a room with limited resources and call that room overpopulated. Cities create false closed systems much like being locked in a room. Overcrowding is not the same as overpopulation.
This has been discussed for over 200 years and the predictions have each in turn failed. These predictions claimed that overpopulation would lead to famine. But failed to acknowledge that famine would reduce overpopulation. But, that’s not likely to happen either since food production is up due to increased farm efficiency. Famine is not caused by overpopulation but generally by governments. Water is also not an issue as the planet is simply covered in the stuff. While much of that is saline that can be changed. Even so a simple reduction in how we use water can easily compensate for any shortfalls.