This would be a good line of investigation if we were certain that these represent towers. Here they are with a couple of vessels from the pharma section:
As you can see, the same elements used in the "free standing towers" are also found in the vessels. Particularly interesting is the rightmost "tower" of the rosettes: that footed stem with a ring around it is typical for metal or woodworked handheld objects.
So my first question would be: why should we interpret these as bizarrely freestanding towers?
As for the style, if they do reference architecture, then it's likely an eastern Mediterranean city with "Holy Land" vibes, like Constantinople or Jerusalem. You'll find some towers and pillars with globe-shaped tops, for example in the Nuremberg Chronicle's images of Constantinople, which I think has overall Rosettes vibes. But nothing as extreme as those six objects, which would have massively exaggerated proportions if they are interpreted as purely architectural.