"Overpopulation"-hysteria is a short-sighted, semi-genocidal ideology (see: People's Republic of China). The same people that a decade ago were worrying about overpopulation in Germany are now clamoring for more migrants from the Global South countries to keep up population growth ("these are our future engineers and doctors"). Proof of how unworkable it is.

European economies would simply collapse without population growth to feed social security. And aging populations are a ridiculously undesirable outcome for any country

Current projections aren't useless. The higher your socioeconomic status, the lower your fertility rate, period. The correlation couldn't be clearer. Geopolitical events could cause temporary changes but obviously wouldn't change the underlying trend. Bringing up the existence of Black Swans to disprove trends is logically flawed.

So there's a clear downwards pressure on fertility rates, in the West, which includes propaganda about "overpopulation" that obviously quite a few people believe in, and that guides their decisions; it also includes socioeconomic improvements. What possible trend could act as an upward pressure?

Is there anything more pathological (psychologically-speaking) than the belief that humans are themselves a pathology

"The higher your socioeconomic status, the lower your fertility rate, period."

Only in a portion of Western culture that has very similar cultural and religious values and also incidentally responsible for a relatively rich middle class.

Counter examples:

Haredi Jews

Hong Kong

Macao

So your predictions are contingent on the assumption that the culture won't change or that specific religions wouldn't be more prevalent.

But the worry about overpopulation has been damn near constant.

Rebuked again and again and again each time we reached the previous "unsustainable" threshold.