As others have said, the midsized cities are going to be your best bet. Ulm was lovely when I was there, incredibly charming especially in the fall when I was there.

Of course there are many types of German cities, so Ulm will show you something different than, say, Lübeck or Bremen. Southern Germany is what most Americans associate with Germany though, which Ulm can give you.

I guess it depends on what you consider as typical German. It is a diverse country and people in Berlin will be different than people in Munich and different again than people in Hamburg - but in any of those cities, people will live their regular lifes if you look besides the touristy places.
There is no “more German” city. But you should probably not visit Neuschwanstein.

Avoid Frankfurt am Main. Being from the UK I sometimes refer to it as Kröydenfurt or Birmingham am Main since it reminds me of both Croydon and Birmingham.

Now don’t get me wrong, Frankfurt isn’t terrible, and I wouldn’t consider the people there “not-German” but I was a little surprised when I went to visit for the motor show, it’s basically not like any other German city I’ve visited. It’s like I asked ChatGPT “create me a European version of Gotham in Cities Skylines” and that was the end result.

I think Hanover is an often overlooked city to visit that I really liked and what I would expect for Germany as a tourist. Hamburg might be better if you wanted something more lively.

A really useful indicator is the concept of “twin cities”. I found them to be pretty accurate.

what does that even mean? least amount of foreigners?

B-Tier cities in the south/west have many of the klischee german stereotypes in terms of old town, cute houses, beer, german cusine

Freiburg

Trier

Nürnberg

Heidelberg

Bamberg

Rothenburg ob der Tauber

I liked Dresden & Leipzig

I heard that the most traditional German city to this day is Dresden. Also on my list.