Some demography experts mention that financial incentives do work starting from the second child (if provided as a lump sum, and with usage not restricted too much). It's not something that can stop the population decline, but it can slow it down to some extent.
The rest, statistically speaking, doesn't make much of a dent in the established social and religious conventions of any given nation, which the governments generally have little control of.
https://www.econstor.eu/bitstream/10419/216331/1/dp13019.pdf
The rest, statistically speaking, doesn't make much of a dent in the established social and religious conventions of any given nation, which the governments generally have little control of.