Additional costs for sloped land with tree coverage

And try it differently.
Place the garage at the street and maybe the house behind it.
Without exact contour lines difficult, I imagine it like this

Driveway
1st level Garage, entrance, wardrobe, building services
2nd level e.g. bedrooms, office, slope-side storage room, utility room,
3rd level Living.

Each level gets a terrace and a piece of garden
The orchard remains on the slope

You don't use 1300 sqm. With us, somewhere 300-400 sqm are left to wild growth. Steep slope (in the pictures yesterday there was only the flat part) and for what. Terrace, playing, flowers, some kitchen garden is easily accessible. You can even cleverly adapt a kitchen garden to the slope with your own efforts. Then you even have a kind of raised bed. Look on the internet and garden magazines. There are such great ideas without needing an excavator and huge amounts of concrete.

If you plan skillfully, you can use the excavation for terrain modeling. This reduces disposal costs and gains mass to straighten one or another surface. The three-dimensional thinking of shapes and masses overwhelms laypeople.

Man nutzt keine 1300 qm.

There he is again, that "one".

Exactly this "one"
do you use your entire slope as a terrace?
Much is planted because it is pleasing or because distance to the neighbor is desired.
There are raised bed solutions for kitchen gardens with the slope etc.

What is "use" anyway. We don't do everything at once, but we will definitely work on, plant, and create small places of rest on about 4000sqm...

Exactly, but it is not made level.

Do you already know the development plan? Because it can really put a big stop to your plans to "raise the house." Keyword "eaves height."

We are also building on a slope right now, excavation about 800m³. Costs for earthworks here about 35k. This is what it looks like:


This is what it looked like before: