Didn't some recent study show that the worry of overpopulation isn't really an issue as there appears to be a critical point where it slows down significantly b

Didn't some recent study show that the worry of overpopulation isn't really an issue as there appears to be a critical point where it slows down significantly because of individual wealth going up which results in less children? Large population growths seems to be directly correlated to poverty and our focus should be to get everyone out of poverty.