Are additional costs for suspended land calculable?

I would even do it that way if there was money left over. Leave the ground as undisturbed as possible where it is untouched and enjoy the native biodiversity.

Not everyone wants that. I myself have a large piece of wilderness. There are plenty of birds.

That's true, not everyone wants that - it is an active contribution to environmental protection. Many people do not know that lawns, cherry laurel, and other non-native species represent a form of green desert for the local nature. As always, it is a question of balance. Of course, people should enjoy a lawn - and at the same time provide a few places for healthy nature.

Because the retaining walls with L-stones at a height of 3.05m were the topic here, I wanted to provide the costs from our civil engineer for price comparison. We have 5m of retaining wall with 3.05m L-stones. The offer is 4080 EUR and includes: 5 concrete support angles 100/305 cm, construction height 305 cm, construction width each 100 cm, smooth surface, concrete grey, delivery to the construction site, support angles set in lean concrete layer from C12/15, thickness up to 10 cm, installation, including sealing of the joint seams with a bitumen welding strip, width up to 15 cm Is something missing from the offer? It seems very cheap to me. However, the prices overall are very good (i.e. excavation, removing and disposing of root stocks, transport, graveling etc.).

Sounds like delivery and installation. Where is the earthmoving?

Earthworks are an additional item.

530 sqm topsoil removal and side storage, average removal thickness 20 cm 950 EUR
650 m3 soil for excavation pit to be excavated according to profile and stored on the side, excavation depth up to 3.50 m 4500 EUR
300 tons limestone gravel free on site, installed and compacted layer by layer as base course material under the floor slab, paved outdoor areas and working space of the support angles 6900 EUR
85 tons limestone chippings 8/16 delivered free on site and installed in a single layer as a capillary-breaking layer under the floor slab 2650 EUR
and then a few small items like stud foil, site setup (1k), geotextile (860 EUR)

We will first store the excavation on the property and after backfilling and terrain modeling see if there is much excavation left (probably not much).
The property is large enough 1400 sqm

And does anyone know if limestone gravel is better than recycled gravel?
Recycled gravel is listed as a potential item and cheaper than limestone gravel (both 0/60)

We will first store the excavation on the property and after backfilling and terrain modeling see if there is still much excavation left (probably not much). The property is large enough, 1400 sqm

Instruct your workers not to drive all over the place and to avoid as much soil compaction as possible. Your garden will thank you.