The Dialect in Bavaria is extremely strong. I speak German very well yet when i was with friends in Bavaria they would ask do you understand what we are talking about ... I would say not a single word. The Germans in Berlin also speak with a thick Dialect which is nearly impossible to understand. Book German is primarily spoken in the Cologne and Dusseldorf area middle Germany. Going North or South of NordrheinWestfalen you will run into dialects. Some are very difficult to understand even for the Germans themselves who live in the middle of the country. I have been with Germans who won't understand a single word in parts of the country. Germany is not a large country either.
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 . . .