Old building with architectural planning from 2020 - cost estimate update

To explain the status quo, below is a g-maps excerpt.

This once again clearly illustrates how clarifying images can be. I had previously understood you to be buying an entire semi-detached house, of which one half had been replaced by an ugly new building during the GDR era, and that the whole thing was so tiny that without the new-new building of the one to be demolished it would not suffice. Now the picture shows what you actually want to buy: one half of an entire semi-detached house, where the neighboring half has been suitably extended in style, and only yours is ugly. Such worlds sometimes lie between textual (comprehensibility) and reality!!! It’s best to add floor plans and sections as well. In the GDR, a lot of ugly things with good substance were built, which are both well reusable and devilishly hard to exorcise like weeds. And often you can make them pretty, too.