Cost issue for earthworks on a slope

Thank you very much for the many responses in such a short time.
Asking the "new neighbors" is not that easy, it is a new development area and a maximum of 1/3 of the houses are standing, and these at most in the shell construction phase. I would have to be lucky to be on site and meet a builder, then I could certainly get information about the soil composition.
The houses in the background have been there for a while, I think I can forget about getting information about the soil there.
I am attaching a few more pictures again, showing what my current idea would be, a height map, current houses and their protection, however with a 4 meter height difference over 20 meters width. The picture with the 2 houses under construction shows one with a basement (right) and on the left only with a slab, I had imagined the left variant. The easiest thing would of course be if I randomly meet the builders. Since my currently reserved plot has a street to the right, I save myself the retaining L-stones compared to that.
I would plan the garage or carport either on the left or right, whichever is easier to implement in the end. This may be exactly on the property boundary.

Is there no plan with more high points and a few length measurements? And, are the currently submitted plans oriented to north? Are there building window restrictions? Does the property need to be accessed from the current bottom of the plan?

my currently reserved plot has a street on the right, so I save myself the support L-beams compared to that.

How do you come to that?

Because of the geology, I would first ask the neighbors if there are any special conditions.

Asking the "new neighbors" is not so simple, it is a new development area and at most 1/3 of the houses are built and those only at the shell stage. I would have to be lucky to be on site and meet a builder, then I could certainly get information about the soil conditions.

I would first relate the term "neighbors" in this sense to 3/5 and 3/6, whose houses have long been finished.

I am attaching a few more pictures again showing what my current idea would be, [...] The picture with the 2 houses under construction shows one with a basement (right) and on the left only a slab, I had imagined the left version.

You can actually see there that the neighbor "left version" is estimated to spend 40% of the costs, for which his neighbor builds a basement usable on the mountain side and residential on the valley side, wasting his money solely on founding his slab unused at crawl space height and frost depth. Many avoidable costs, not even formally under the cost center "earthworks". Pretty dumb, you shouldn't want to copy that. The outline probably shows a rectangular house (left side) with an attached double garage (right side) and comes from a specific house idea. If you have not used the basement potential in this, you should discard it or fundamentally revise it. As far as I have correctly interpreted your building composition, I would like to add the advice that you would do yourself a big favor by omitting a house-garage passage and setting the garage deeper than the house - I would even separate it here, possibly at the right planning boundary of the plot. Also read externally (= include quotation marks) "With or without basement: a rule as a decision-making tool".

Unfortunately, only that, more information probably only after purchasing the plot (surveying, soil report). Yes, the plans are oriented to the north, I had forgotten to mention that information. There are building window restrictions, as the house/foundation slab drawn in the picture falls within these development limits. The front door faces south, the right side (east side) is basically garden/hedge. As I am not an earthworker, I simply assumed that otherwise L-blocks would lie directly at the street to the property; I can't imagine that being allowed.

You can actually already see that the neighbor in the "left variant" is estimated to waste 40% of the costs, while his neighbor builds a usable basement on the mountain side and a residential basement on the valley side, just by founding his foundation slab unused at crawl space height and frost depth. Many avoidable costs, not even formally in the cost center "earthworks". Pretty stupid, you shouldn't want to imitate him.

Thanks for the open and honest answer, that at least helps me with the whole project. As I already wrote, I am at the very beginning, so I was hoping for experienced help here. When I read that, maybe it is not so smart to build on a foundation slab, even if the height difference at this house is a good 2 meters more. The garage topic is currently not yet planned, as I am still hanging on whether I really want to try it with the plot or if I end up with too many problems/costs. Currently, I am collecting ideas and suggestions from you.

Thank you for the open and honest answer, that already helps me a lot with the whole project. As I already wrote, I am just at the beginning, so I was hoping for experienced help here.

Most of the help you will find here with the simple trick of reading a lot of other people's threads. For beginners, at the same place as my basement posts, you will also find the "A house construction schedule, also for you: the phase model of HOAI!".

When I read that, maybe it is not so wise to build on a slab foundation, even though the height difference at the house is a good 2 meters more. The garage topic was not yet planned at the moment,

With a 2m height difference under the house floor area, you pay 100% of the basement costs whether you build it or try to avoid it. Did I misinterpret the house outline and are you planning an angled bungalow?

since I am still debating whether I really want to try it with the plot or if in the end I will have too many problems/costs.

Your biggest cost trap is the layer 8 problem (punctuation emoticon missing, not my fault).

I am actively participating in this forum but specifically to get an answer to a question about an existing plot of land, just reading is not enough.

With 2m height difference under the house footprint you pay 100% of the basement costs regardless of whether you build it or try to avoid it. Did I misinterpret the house outline and are you planning an angled bungalow?

OK, I was not aware of this, I might have found that out in one of the many topics. So I can discard the current planning anyway. It was an angled single-family house with 2 full floors.

Your biggest cost trap is the layer 8 problem

I just like to hang on the garage.