Farmland turns into building land: landfilling, foundation costs, and procedures

In our development plan, the areas of junctions were rounded off and then also not allowed for driveways. What does your development plan say about that? Whether the city will allow boundary construction on the main street is questionable. Your architect should know something about that.

@11ant The house is 100% within the building window. Even though the OP has covered the lines.

Ah yes, he really "cleverly" drew it – it is actually fully inside a corner of the building window. I still don't agree with the positioning: I would align the house axis with the contour lines (whether they are those of the original terrain or also those of the finished terrain, since the entire area will probably not be raised by a meter), and I wouldn’t block the evening sun with the garage. Many prospective builders take the saying about building the first house for an enemy too literally and as a guiding principle: unfortunately, it is just nonsensically clever to "park" the house in the north corner out of stinginess for south-facing areas and to use the garage as a noise and view shield from the street. And taking the heights lightly also backfires (as does the architect aversion, by the way).

In our development plan, the areas of junctions were rounded off and then also not permitted for driveways. What does your development plan say about this?

Nothing. Also nothing about height of finished floor or the like.

because one probably won't raise the entire area by one meter

I don't want to be a low point. I also don't consider this practical here, as the house is in the north and streets in the south (with driveway) and west set the height (both at almost the same elevation).
I test positions in Sweet Home 3D online for this.

I don't want to be a sinkhole. I also don't consider this practical here when the house is in the north and the roads in the south (with driveway) and west determine the elevation (both at almost the same height).

In this matter, I understand that, but you first have to be able and willing to afford the financial consequence. If I imagine spreading out the difference between a carport instead of a garage, a tub instead of a whirlpool, terrazzo instead of Carrara and so on over the property with the excavator bucket, honestly, the shirt would be closer to me than the jacket.

I test positions for that in sweet home 3d online.

SH3D only displays the whole thing graphically for you, without allocating the costs of earthworks to the living area square meters. If you convert the cubic meters of the full-surface linear embankment of one meter at a floor area ratio of 0.4 to the house base area, that practically amounts to two and a half meters height converted to the house base area—according to the 11ant basement rule about 125% of the basement price. In other words: without lying to yourself, you have to add this chunk to the land price (at least without having to pay property transfer tax on it). But with this casual generosity when shopping for civil engineering, the property becomes luxuriously expensive. Mind you: you only have to finance it more without the completed security becoming even a crumb more valuable. For that, I would be stingy even with my own money, let alone borrowed money.

If you still absolutely want the property, in your place I would: 1. build with a basement, let the ground floor be a raised ground floor as seen from the street, and 2. only embank the terrace area as well as 3. embank the driveway to the garage and make it only the required 5 meters long.

I keep wondering how many prospective builders buy something as a "building plot" that is practically a rainwater retention basin that they first have to fill in to make it usable (and meekly endure this as fate and are even grateful for the opportunity). Home builders go into debt to acquire plots where every investor would give the municipality the bird or first want to see an appropriate price reduction. Municipalities sell raw what actually should have been developed topographically first and then regularly, and even more brazenly, develop "off the cuff." In the Middle Ages, such mayors would have been paraded around the marketplace in the pillory, nowadays home builders feel like little lottery winners as land buyers. My late grandmother would have said "there is nowhere as crazy as in the world."

I keep wondering how many prospective builders buy something as "building plots," which in practical terms are actually stormwater retention basins that they first have to fill in to make usable (and they meekly endure this as fate and are even grateful for the opportunity). Home builders go into debt to acquire plots where any investor would think the municipality is crazy or would first expect a reasonable price reduction.

Of course, you get annoyed about the extra costs for filling in, but in the end what counts is the result.
And I much prefer to pay 20k for filling in than to give it away to a realtor.
We decided against buying the plot, among other things because we didn't like the garage and driveway in the southeast.

Especially during the development and construction phase, if you’re not completely clueless and actually talk to the construction workers, there’s also the possibility to get soil from the neighboring property or directly from the development. I also had to do some filling because the plot was about half a meter below the finished road... when laying the foundation, the excavator operator dumped and spread 150m³ from neighboring plots for me. For free, he only charged for 2 hours of excavator work. And later, when the green strip was done, the excavator operator dumped and spread 3 truckloads of topsoil into the front yard for me... for a two-digit amount... But you just have to talk to people for that.