Of course in Bavaria a 40mm tire would be more comfortable than a 23mm tire. It would be more comfortable in all Germany, even without weight on the bike. 20 years back we used 23mm on road bikes, even on road bikes people use 28-30mm these days.
But if one wants to feel every single little pothole in his body 23mm sure is fine.
There are no potholes in Bavaria. Potholes are not a known concept here. I entered Bavaria via Lake Constance and exited today via Füssen, didn't see a single pothole the entire time. Same story in Baden-Württemberg where I was before Bavaria. Forget potholes, there are hardly even cracks on the roads here. Even single lane farm roads in southern Germany are smoother than the road in front of the freaking White House. I don't know what else to say other than that the German government clearly has a much higher road budget than America. But we all already knew that right? They are famous for their country's immaculate driving experience.
I'm fully on board with the idea that wider tires will indeed smooth out bumps. But what bumps? The wide tire has nothing to smooth if there are literally zero bumps in existence.
Adapt you tire width choice to the conditions of your chosen touring route, that's all I'm saying. If you're touring in an area that has bumpy roads, wide tires are a great idea. And don't forget to consider the entire route. I could tour on 28s in Germany, but 28s wouldn't be wide enough when I get to the Balkans next month, so I'm using 35s even if they are pointless in Germany, because I don't want to change my tires every two weeks.