Every single one of those issues has been around with modifications my whole life, and my parents' lives. I'm American so my context is narrow, but . . .
Nuclear threat? We used to do "duck and cover" drills in school in the 70s.
Climate/pollution? Try the air in LA in the 1970s.
Poverty? The poverty rate in the US is near an all-time low.
Demographics? Has opportunity expanded or contracted for non-whites in the US over time? For women? For LGTBQ people?
Lack of factual science? Do we know more or less about the world and the universe than we did? Church attendance in the US is near an all-time low.
The data doesn't support the hand-wringing, writ large. Everyone has their own experiences and circumstances, and there's always plenty to be worried about, and I am frightened by Trump and MAGA, but every generation of old people have thought things were worse than 50 years ago since the 1800s. They've nearly always been wrong.