[*] All parts of the Israeli population have high birth rates, even the secular Jews. I find it misleading to single out Orthodox Jews as the main contributor. You don't do that to Evangelical Christians or Mormons, or some other groups in US.
I don't think the religion is the driver here.
Here are the figures by group in Israel [1]:
- As of 2022, the fertility rates in Israeli cities dominated by specific demographic groups were: Haredi 6.1, Bedouin 4.4, Jewish non-Haredi 2.4, Arab 2.2, Druze 1.8
So the GP's characterization is correct.
Yes, non-Haredi Jewish Israelis have a higher fertility rate than in Western nations. There seems to be a variety of reasons for this including cultural/religious pressure, institutional support and selection bias (in terms of who chooses to immigrate/emigrate).
It looks like a regional phenomenon - countries near to Israel have a similar fertility rate.
see (Middle East fertility rates) https://data.worldbank.org/indicator/SP.DYN.TFRT.IN?location...
and (OECD fertility rates)
https://www.oecd.org/en/data/indicators/fertility-rates.html