As it happened, I learned German in school from a German native speaker - from up north next to the Danish border.
Then the US Army sent me to West Berlin, where I discovered that nothing I had been taught was more than slightly intelligible to anyone there.
Years later the US Army sent me back to Germany, to Aschaffenburg in northern Bavaria, where neither the Far Northern Hochdeutsch dialect nor the Pruessische deutsche dialect of the Berliners were understandable.
And the total distance between Denmark, Berlin, and Aschaffenburg is less than the distance from one side of Washington State to the other west to east. And I can understand the folks in Spokane fine, as long as they aren't speaking German . . .
And Civ VI's Ludwig is not speaking a Bavarian dialect, which non-Bavarian Germans described to me as sounding like the speaker was both drunk and clubbed over the head repeatedly just before he started speaking. Since I spent most of my time in Bavaria in various bars, I can't say from personal experience that Bavarians in that situation sounded any different from anyone else . . .