With a larger population combined with more of a chance of living past the age of 5, you need fewer births to get the same population growth rate globally. As the world population rapidly urbanizes we will settle into a new normal that will still approach Earth's carrying capacity faster than we can adequately react.
Human population has overshot in 1971[1], what are you talking about? Carrying capacity has long been exceeded, we’re living thanks to the phantom carrying capacity[2].
I see marriage rates falling by about 50% over the past decade. But this claim seems unlikely, or perhaps just badly skewed by the seasonality of things.
He is probably talking about the "520" Marriage Day. May 20 is a popular national marriage day (due to tradition) and many couples choose to get marry on that day in China.
This year's 520 marriage rate is ~40% of last year's.
https://news.sina.cn/gn/2023-01-17/detail-imyanfvn6707213.d....
(Figure 3)
2017 - 17.23 million
2018 - 15.23
2019 - 14.65
2020 - 12.00
2021 - 10.62
2022 - 9.56
Note that this is official Chinese gov statistics. Their numbers are known to be untrustworthy.