Also, not enough children can be problematic - just look at Japan, which has an aging population and not enough people to work.
Ideally we would have done this when the word was at about 2B, but it's still better to start at 8B than 14B.
And my point about the US is the same[0]. Rather than aiming to keep the population size stable, I'd think goals should be around the size of the working age population, and around a level of growth that's required for the US economy to grow.
I do take your point about the number of people on the planet, but I don't think it's really an issue outside of developing nations.
[0] https://eig.org/wp-content/uploads/2019/04/Heartland-Visas-R...
Basing an economy on an ever-growing population is foolish. We should plan better than that.
Also, I'd argue society would benefit if everyone had fewer children. We'd all be much happier and better off if the world population was half what it was today, I'd wager. We should strive to stabilize the population, not grow it endlessly.