Germany has dozens of links to its neighbours. We don't need much in terms of "black start" capacity, that's just pointless fearmongering by fossil fuel and/or prepper propaganda sites.

As long as even a single link to any of our neighbours is up and running, it can be used to start the rest of the grid - which is exactly what was done in the 2006 outage and why that one took barely two hours to be resolved. The only truly screwed country at the moment is Portugal because all their grid links run through Spain.