Additional costs for sloped land with tree coverage

Hello dear ones,

after the last plot we could have bought was ruled out because of the soil/slope, we have now actually found an absolute dream plot.

Cul-de-sac, large, surrounded by meadows, stunning view and exactly where we would like to build. It is also cheap. Dreamlike, right? At least actually.

Now to the "actually": The plot is on a slope and there are some trees on it. I have informed myself about the trees so far: They may be removed, but each time a replacement tree must be planted. No problem, since we wanted (fruit) trees anyway, but we can also get along with others.
Now the slope worries me. It has about 18 to 20% incline. The incline is relatively even. The plot is about 1300 sqm in size and approximately 32 by 40 meters.

How cost-relevant is such a slope? Since we definitely want to build with a basement anyway, a basement does not represent a disadvantage or extra cost compared to a slab on grade for us. But what else do we still have to plan for because of the slope?
What is the price range for leveling the garden?

It is about a house with a built-up area of approximately 12x10 m. The soil is clay and sand.

Thank you very much. I am looking forward to your answers

Calculate at least 40,000 euros for excavation/ disposal/ slope stabilization/ drainage + X for soil replacement if the clay causes problems. It can easily be 20 - 30% more. It is difficult to predict without further information. You can reserve the same amount again for landscaping.

For the trees, it depends on the size. But you can also plan 250 - 500€ per tree and stump here. For a deciduous or coniferous tree, we also have to plant 2 fruit trees as a replacement.

The trees are negligible property. The slope itself will really bring you (financial) fun. 18% is approximately 10 degrees, so with a length of 40m about 7m height difference. Lots of earthworks, securing measures, property adjustment due to the slope, water, etc. Clay is also not really ideal for foundation, to put it mildly. I would have also estimated around €50,000 +X just for the groundworks + the more complex construction.

I am also at nordanney and the property is not leveled. Only for the area of the house, garage + a terrace on the upper floor

Thank you very much for your answers.

To clarify, here is a sketch of the property.

I imagined placing the house more towards the "top" and having a slightly longer driveway. This way, I could build the house higher up and wouldn't have to remove as much soil. The removed soil could then be used to refill the lower part of the garden. The disadvantage would be having a somewhat steeper driveway to the house itself. However, everything would be on a higher level.

Cardinal directions?

Basically, I don't think that's a good idea. Why would anyone want a long, steep driveway? What you might save on excavation is eaten up by the higher costs of the driveway and internal site development.