It has dramatically higher thermal heat demands in winter - far higher than is compensated for by that. Even if everyone switched to heat pumps.

True, but higher demand for heating in winter is not specific to Germany. In the end, Germany will likely need to import energy anyway - just as it does today. But this means this question may not be the most relevant.

Huh? It highlights the relevance. It’s easy to handwave ‘imports’ away - but import from whom, and how do they make the energy?

One could import it as ammonia from locations that can produce a lot of it via solar.