Additional costs due to hillside location and trees

Hello,

maybe you could give me a cost estimate.
A single-family house without a basement, about 107 square meters, is to be built. In the rear area, the floor slab must be raised by 70 cm due to the slope.
Additionally, there are 7 trees in the area of the floor slab that need to be removed. When removing the roots, deep holes will be torn open, so a complete foundation cushion will probably have to be created.

What could that cost?

First, I would level the foundation slab, that is 35 lower in the front, 35 higher at the back. This allows for a gentler slope, and you might be able to do without angle supports at the back. Of course, the sewage shafts should be deep enough to dispose of feces, etc. without needing to pump them up. I can't say anything about the trees. If the leveling works, it should probably not exceed 8 thousand. Our house is very similar. 13.5 by 10. Living space. Comparable. Built uphill. No trees. The leveling resulted in an earthworks invoice for soil removal, sand delivery, and excavator hours of 6700 including tax. We can do without a retaining wall; a staircase from the street to the house will also be unnecessary later, as a pure path uphill will suffice.