There was the German ethnicity, and a mosaic of Germanic languages.
But again you can continue with trying to make it seem as if everything is equal to everything else.
I'll leave you with this little thought experiment. If we put a northen German, a Swiss German and a Spaniard in a room, how long will it take for the two germans to realize they have more in common with each other than the spaniard?
Switzerland is actually quite different from Germany.
People often laugh about the Holy Roman Empire (mostly people who have not studied it) but it did actually serve as a distinct legal and cultural tradition for much the area that is now Germany (and more).
The language are different but not that different, with some effort you could understand each other. Many Germans from different parts fought together in mercenary bands or for Holy Roman Empire armies.
During the Revolution in the 1850 they tried to establish a unified Germany, so clearly the idea had wide recognition by then. You don't have movement like that spring up out of nowhere. After the Napoleonic war, German Confederation was a very recognized and understood fact.
Sure if was not fully 'unified' but neither is French or Spanish culture.
- Peter H. Wilson, The Holy Roman Empire: A Thousand Years of Europe’s History
- Helmut Walser Smith, Germany: A Nation in Its Time