Bringing in more people is just a lazy fix and does nothing to fix the underlying problems.
If there are problems with society, we should fix them for their own sake.
Population growth cannot continue forever, nor population stability at an unsustainable aggregate consumption level.
https://e360.yale.edu/features/our_overcrowded_planet_a_fail...
And beyond that, poor mental health and knowledge of what kids can be like also means young people just don’t feel ready to raise a kid for quite a while.
These factors won’t go away without serious changes in how our economic system works.
I would also ask if it really matters that the birth to death ratio is more than one. One seems like a good baseline to maintain.
I'm not quite sure anyone has a monopoly on a definition of what this could be, and very much subjective to various forms of "cultural hangups" that might be prevalent around the world at any given time.
1) If not handled well that can make a huge mess. see Germany 5 years ago for example
2) If the people immigrating aren't well educated or capable of communicating with the rest of the people but are allowed to vote then malicious politicians can use that to distort the democracy which is pretty dangerous.
3) There are some pretty nasty cultures there. I'm not about to go preaching that we have it totally right but some of the stuff going on in Asia and Africa is totally unacceptable.