Single-family house optimization and planning (180 sqm + attic without basement)

I just don’t have a scan of that right now

I do. Has it been clarified with the approval authority that you are planning beyond the development plan boundary? With it was just a noodle line, but here – different development plan, different number of floors, different plot ratio/floor space index ... You don’t need the private road, but you are adjoining property owners. Are the costs for it settled? And the door in the garage – aside from the fact that its purpose is not clear to me, it would be inadmissible on the boundary.

Unfortunately, it really makes no sense to discuss a pipe dream. If you yourself say that 380k is your maximum limit, I see a maximum of 150 sqm without a massive double carport. And the assumption is quite optimistic and requires costs of 2,000 €/sqm, which you might still achieve in rural areas of Niedersachsen? Logically, there are no large window fronts or external blinds included. Not to mention smart home systems (whether wireless or wired ...). Also consider that even without a basement and with a kitchen, you still have quite a few (construction) additional costs. In our regions here, you get a 120 sqm terraced house from the developer with this budget, without any special features.

I wouldn't see it as quite that extreme. We are planning 175 sqm and are within the stated budget. However, for example, we have held back financially on the windows. We are forgoing French balconies and sliding doors; looking at the house, that amounts to 10 to 20 thousand euros. We will build the carport ourselves later out of wood, which is cheap, and if finances really don't allow it, it could also be postponed indefinitely. Two full floors, city villa, flat roof, things like that cost enormous sums depending on the case, unfortunately you have to inform yourself and make compromises.

I also said that it applies to our region. With us, you certainly don't build for €1,800 - €2,000 per sqm, even with a low standard. I didn't just make that up, but see it from the offers. A well-equipped terraced house here starts at €550,000 excluding incidental purchase costs. Where are you building in BaWü? There are still some differences in Baden-Württemberg as well. Of course, there are always adjustments, as I mentioned with the carport, for example. But the OP initially didn't plan any of that. Since we're talking about the OP from Lower Saxony here, it probably looks different there, but even so, 170-180 sqm is simply unrealistic.

We build in the Ortenau district and there also in an expensive area, not "in the middle of nowhere"
But these are only the pure house costs, there is no floor slab included and of course no incidental construction costs. We build with a prefab house manufacturer, which of course also affects the price a lot.

We are building in Ortenaukreis and also in an expensive area, not "in the middle of nowhere" But these are only the pure house costs, there is no foundation slab included and of course no additional construction costs. We are building with a prefabricated house manufacturer, which of course also affects the price a lot.

Unfortunately, you also have to pay for the foundation slab and the additional construction costs. And the additional construction costs are actually almost always the same up to a certain size. In my opinion, the OP is talking about my total budget. Therefore, your comparison is somewhat misleading when you say that you manage it too. Especially since you apparently still have to deal with planned and not actual costs. I don't understand why the prefabricated house manufacturer should make it particularly cheap now. Construction costs are quite similar regionally. The standard and the wishes determine the price.