Their economy was stagnating for at least a decade before 2018. They've gone from near-zero growth to negative. It doesn't matter what the reasons are, really. The pandemic hit everywhere, and their choice to "value free time" is the problem here. Turns out you can't sustain a high quality of life without enough people working hard to produce the products and services that create this high quality of life.

Where’s the evidence Europe is failing to maintain it quality of life?

You’ve implicitly supposed that quality of life can’t be maintained without economic growth, but have provided no evidence or rationale for such a claim. Quality of life measures seem to indicate things are getting better not worse in Europe, and is leagues ahead of the U.S.

Yet if you look across the EU it's the richest countries that work the least hours. The people working long hours don't seem to be getting much benefit from it at all.

You seem very confident that the economic problems are entirely due to valuing free time.

Do you have any evidence to back up this assertion, or is it just instinct?