What's interesting is that before covid hit, Germany was in the midst of a successful project to pay off its government debt. They hit about 82% of government debt to GDP in 2010, and went below 60% in 2019. All with low inflation.

See https://en.wikipedia.org/wiki/Debt_brake_(Germany)

It's important to note that it was done not in the small part thanks to the rising debt levels of other EU countries. In my opinion, you should view EU as one system.

Yes because Germany exports to other countries by lending them money. The export strategy is entirely debt fueled but that won't stop it from being called export champion and it is really a lending champion.

Why does that matter?

What does this have to do with German government debt?

How is that mechanism supposed to work?

Are you somehow assuming that the total amount of government debt is fixed?