Birth control vs. the commandment to multiply and multiply

Shalom Rabbi, in recent years, an opinion has begun to take shape in the scientific community that says that humanity needs to begin reducing the birth rate because if we continue at our current rate of growth, it will cause difficulties in the future. So what comes first: the commandment to multiply or the scientific recommendations?
On the one hand, I can say that if I have more children than scientists recommend, then it doesn’t matter that much because as an individual – I’m like a drop of water in the ocean. But on the other hand, if everyone thinks like that, then the results will be disastrous (according to the parable of the king and the cola bath).

And on the same subject: According to what I know, the basic obligation of the mitzvah of Pro Vervo is to have one son and one daughter – is there really added value in having 7, 8, 9 children? And if so – does it precede the scientific recommendations?