I don't think Project 2025 is about a white ethno-state. I think it's about a conservative pullback of social liberalism, and Liberalism/capitalism in general.
They want nuclear families back. And surprisingly it won't be women who suffer the most unless you don't count death as suffering and slant it towards long-run suffering, it will be male incels who supposedly most are radicals, and the plurality is radical left-wing (Not progressivism but like Maoism). It will be people who cannot get wives and girlfriends, and LGBTQ people who aren't in the tech industry or aren't rich enough to leave. They will also attack liberal women who choose to get a pet instead of a boyfriend. A lot of people will be shunned, outcasted at best, or at worst sent to prison to work in labor camps.
Now I understand the democratic DAs who were against large-scale mass prison systems they didn't want to fuel private prisons that right now are having a field day.
It's American 1950s traditionalism for the 21st century. The human clones aren't ready, the radical life extension isn't ready, and immigration is too temporary to fix the birthrate problem. An immigrant will get a family, their children however may not.
I don't think it's even about China having 1 billion to the US's 350 million, it's about American power. America has picked being a powerful country over productivity, and climate change from having a lower birthrate. The democrats aren't against this, they are already having candidates like the New York Senator in Congress say they will interfere in races with 'newcomers' aka progressives who would be the most likely to reverse this.
It's an interesting calculation and mass policy movement. America loves to learn from failure, Japan is a failure they have a low birth rate, as is South Korea, and even Switzerland, and the EU countries. Even Immigrant-heavy Germany does not have the population growth to be a dynamic country. We have never been a full democracy like your Nordic countries, people in prison can't vote for example.