Japan and Poland have been stable, maybe slightly declining, since the early 2000s

I just checked Poland and it's not what they are reporting:

https://forsal.pl/gospodarka/demografia/artykuly/9811360,gus-potwierdza-to-rekord-dzietnosc-spadla-nizej-niz-kiedykolwiek-wcz.html

Number of births:

Birthrate:

Systematically falling for the last 10 years. Yes, it was better before that but experts say it doesn't look like stopping anytime soon. But I guess we'll see.

Those are data from GUS, the official statistics bureau of Poland.