Costs of garden landscaping and outdoor facilities at a single-family house on a slope

(...)
But in the end, it's quite different because it's not on a slope (hard to assess what hours result from the increased logistical effort) and also not in the same region (different companies). So as long as I don't get other offers, concrete experience from other slope projects is probably the only thing that would help me evaluate the €190k offer.

Aha. Let me tell you, a slope, especially such a cliff you live on that requires 50 or more steps, is a massively greater effort. Precisely because you have to stabilize again and again.
That means a lot of gravel, a lot of concrete, a lot of drainage, a lot of gravel, and many hours with really large machines.

Here in the neighborhood, numbers for a complete garden on almost flat plots are circulating between €50,000 and €80,000. A few L-shaped stones, some standard paving, 2 steps to the front door, a double-wire mesh fence, and otherwise lawn.

If I imagine that on a cliff, with 50 steps, huge concrete formats, the entire earthworks for 100m² of paving alone... the €190,000 seems quite plausible?

And then this 23m support with basalt palisades... as I said, that alone will already be around €30,000. Right? ;)

(...)Then it just takes 3 or 4 years. It’s not like it’s unusable. Much of it is just aesthetics

But then it will become significantly more expensive. Because setting up/clearing the construction site, meaning bringing in equipment, carrying tools up, first creating space to work, then cleaning up, returning tools and equipment, cleaning, maintenance, etc... The landscape gardener doesn’t charge just once for all this, but 3 or 4 times. These are setup times that the customer naturally pays for; they’re not given away for free. And probably paths have to be created again for the heavy machinery first, because the first thing you get done will be the access path to the house. The crawler excavator can’t just drive over there easily anymore to get into the garden up on the slope. I have the same problem, although on a much, much smaller scale. For 2 years I haven’t been able to build a shed because the garden isn’t finished yet and with the shed no large machinery (excavator, wheel loader, etc.) can drive into the garden anymore. You always have to keep that in mind...

To what extent the concrete offer is really good or too expensive cannot be conclusively assessed by us here. From what you write, it appears plausible. No more, but also no less.

"Too expensive" is always a steep slope. Every square meter you make usable means that somewhere you have to add or remove something and take care to support what would become too steep and provide drainage. Additionally, different soils move more or less easily. With everything you do or have done, you have to expect deviations. Doing it yourself is more strenuous than on flat land, and before you see good results, there will be more sweat.

What helps: Set priorities and accents. Only a little is really necessary, such as a path to the front door. Think three-dimensionally. You can build into the slope, along the slope, or over the slope. The latter is, for example, sometimes a good option for part of a path or a terrace. What you build over with a foundation and supports does not need to be extensively backfilled and retained. What already has good root structure holds up to 60 degrees. Better to build with the given conditions than against them. A standard-format staircase with a walkway can be cheaper than building a staircase into the slope. Travel to steep areas in other regions where you find the aesthetics pleasing—e.g., Tuscany, Provence, Picos...—and gather ideas. Not all people there are rich. Look at how steep sections on hiking trails are designed (usually inexpensive, low-material, and durable). Buying a used mini excavator is worthwhile for the size of your project. Two neighbors have done this here. We only have a tracked dumper with a Honda engine, which can transport material up to 300kg almost anywhere.

Consider a timeframe and do one project after another. Appreciate every progress.

It has proven itself with us. We do not know the conditions. We do not have only a 14 m height difference, for example, we do not have a 90-degree angle, road above and below. We do not know how it is with the OP.

You really have good lines of thought that definitely help us to see the whole thing from other perspectives! Thanks for that! I believe we long for an assessment of the price mainly because we know the "price variety of companies" from other trades and of course don’t want to take "the most expensive one" (probably also with an "I-don't-really-want-to-do-it price") at this size range of 190 k€. Really annoying that all the other companies are playing dead. But it will probably come down to following up here again and trying to get an offer.

We also briefly discussed the topic "splitting the project into 2 or 3 subprojects" with the only provider. The reaction was identical to what MachsSelbst wrote: Not sensible and definitely much more expensive as described.

No, it definitely doesn't come down to that. You don't gain anything at all by pressuring someone who actually can't or doesn't want to make an offer through annoyance.

The one who gave you an offer is willing to do it, the others don't want to. You have to accept that.

You have to be able to operate a mini excavator, especially on a slope. And what's the use if you can't get rid of the excavation or if you tumble down the slope together with the excavator because you have no experience with the machine.