I stayed in Gengenbach in the Black Forest for 4 nights in 2022 and absolutely loved it. The town is very charming with beautiful half-timbered houses (it's frequently called a "chocolate box" village) and has a beautiful Altstadt, with quite a few restaurants and cafes to choose from. It's also a very short 30-40 minute train ride from Strasbourg.
The town church (Saint Marion) is quite beautiful, and the medieval gates to the city are really interesting. The Benedictine Abbey is also worth a visit, and behind it are some cloistered gardens that were a joy to wander through. This was one of my favorite places. It was peaceful and inviting and I could have stayed for hours. There were little signs of inspiration scattered around, and some children from a nearby kindergarten playing on one side.
Also don't miss a walk through Engelgasse and Höllengasse streets (near the TIC). Here you will find cobblestones and half-timbered houses, flower pots and cats resting on doormats and quaint dolls in the window. I felt like I had walked back in time when I strolled through these quaint and narrow streets. There is also a nice hike you can take that will get you above the town with some absolutely beautiful views of below. The hike ends up at a church called St. Jakob auf dem Bergle that sits above town. The TIC in town will have maps showing you how to get there. it was a really nice hike and as I said, the views are just lovely!