I get your struggle, absolutely. In a historic town, the terrain is actually VERY harsh while the aisles narrow, and the lifestyle screams for something small. But that something small might wear out even quicker worse than a large full-size pram like your Bugaboo Fox is.
My thinking would be to get something of quality while being sturdy, medium-sized. The first that came to mind was actually the Baby Jogger City Mini GT2, as that one can tackle quite a lot while not being overly large. A Gesslein S4 is nice in terms of wheel size and suspension.
If something even smaller is on your mind, a TFK Dot2 would make sense to me, but here, always count on small wheels + cobblestones = a bit of noise, a bit of difficulty. So, unfortunately, larger wheels and bulkier pushchair frame are actually going to perform better. Still, the Dot2 is much sturdier than similarly-sized buggies so I would definitely think about that one, even if more sporty and less stylish than your Fox.
Lastly, I will mention that you might want to think of truly small strollers like the Joolz Aer (which I often see downtown literally because of moms wanting something small for the city center), and while that could be the best solution, if the size was a priority, I wouldn't personally suggest such small ultracompacts. The damage over time will show for sure - but you already know that given you see it on a Fox as well.
The reality is, a bulky three-wheeler would do a better job there, but it won't make you happy in terms of compactness and weight.