Check latitutes of largest cities in Germany, and compare them to largest cities in China. Have you noticed how all of major German cities are much further north than major Chinese cities?

You can't ignore physics and climate.

Your argument is basically "It's only 80% as efficient as another country" so it has to be bad?

what if it's already 50% better than any alternative? Solarpunk is alive and well and economies of scale of panels and batteries will make it even more affordable and viable.

China connected 5 solar panels every second of last year. This is happening.