I would name Freudenstadt as the center of the Black Forest.
When did you plan your trip?
You already know a lot of towns around the Black Forest. For me, the most interesting is probably Baden Baden and Freiburg.
On the western side, I can recommend Rottweil and my home town of Villingen. All very small towns but with a lot of charm.
If you can let me know your travel dates and it is compatible with my schedule, I would be happy to show you my home on a tour.