I mean, I’ve always said that the population is a real problem with no good solutions. People are uncomfortable talking about it because there are no good solutions, but that’s no reason to pretend it doesn’t exist. But people act like even mentioning it is the same as proposing or supporting an unethical solution.

I agree with mostly everything you wrote in that, except to say that the problem is mostly manmade and is economic in nature.

Problem: demographic collapse causes a top-heavy (old-heavy) population pyramid whereby there aren't enough young people to take care of the aging population. This is a real problem that we should engineer ourselves out of. Maybe a higher % of the workforce is redirected to healthcare, in part by automating away bullshit jobs like fast food and retail workers. Maybe we make advances in automation/robotics/AI that allows some of the caregiving labor in hospitals and nursing homes to be done by machines instead of people (extending the productivity of the human labor). Those are problems we should be working towards solving, and plausibly could solve if the political and economic will were there. I hope Japan and South Korea get really far into solving this before it becomes a problem everywhere.

Problem: our entire economy is predicated upon infinite growth, and the nanoinstant that belief in future growth falters, the stock market and entire economy collapses in a way that makes the Great Depression look like a quaint blip. This is unsolvable. All of the wealthy, powerful, and political factions would revolt if anything threatened their prospects of unlimited future growth. The entire world economy is a ponzi scheme that requires new markets, new consumers, and perpetual growth even to exist at its current level. When you hear "growth is priced in", that's basically the fundamental corner we've painted ourselves into. The markets assume untenable growth now as the baseline, and if the mirage falters, the economy will tank shockingly quickly. This is the Faustian bargain of late stage capitalism.

As it stands, the population growth has peaked, and the population will naturally peak and then decline. Nobody needs to be killed or sterilized to make this happen - it will happen on its own. The reason seems to be rooted in the education level of women, and the availability of reliable birth control. As someone once eloquently put it: "the average woman would choose to give birth fewer than 2.1 times" (replacement rate).

As a final thought, I will never agree with people who assert that the "carrying capacity" of Earth is far higher than the present population - double or more. This entire premise is based on living like an impoverished person in India or Africa. They will freely admit that the "carrying capacity" is much lower if the baseline living standard is the middle class of developed countries. Most of North America and Western Europe is wildly rich by global standards (fact). I'm here to say that still higher standards are desirable and attainable, at low global impact with lower global populations. We should all be filthy, filthy resource-rich, and to deprive us of that because the Earth "should" have 10-20 billion humans is fucking bollocks.