Designing a garden on a slope sensibly

Parents are on corridor 177?
At what level is the OKFB EG located?
Somehow I can't get the two pictures to match

Parents are in corridor 177?
At what level is the OKFB EG located?
I somehow can't put the two pictures together

Correct, parents are in corridor 177.

We have a ground-level entrance in the basement. It is located at 222.40.
Can it be better recognized in the pictures now?

Why is the house sitting so high? Can you post a site plan with the house marked? What requirements do you have for the garden? For example, utility garden, where terrace, play area, dike, access to parents, etc.

This was the consideration for our terrace

I am standing on your terrace. To the left of the house, a path for wheelbarrows and such; a slide fits well there. In the area of the black beams, I would plan a level area, it should be around 225. At the highest point, I would catch the slope with a shrub bed. Whether you use natural stone or L-stone for this does not matter. Maybe you should already plan a smaller offset to the right of the terrace that lies deeper. In front of it, a high retaining wall that separates the upper part from the lower one.

I am standing on your terrace Left of the house a path for wheelbarrows and the like A slide fits well there. In the area of the black beams I would plan a level area, it would have to be about 225. At the highest point I would catch the slope with a shrub bed. Whether you use natural stone or L-stones for this does not matter Maybe you should already plan a smaller offset to the right of the terrace that is already lower. In front of it, a high retaining wall that separates the upper part from the lower one.

Thank you very much for your ideas! Do I understand you correctly that you would already fill up quite a bit of soil in the terrace area (your black area) in order to then possibly go out somewhat level? And then possibly plan a step towards my parents? How would you design the rest of the garden then? It remains sloped, right?

Is it still that much? The natural terrain should already be at 225 m there, right? Do you have a picture of the current condition? Maybe I put it together incorrectly. Maybe you can also set the rear area between the lines again. But you wanted as few terraces as possible. Where it says path, I would model a slope for the path and slide. I would plant the area with low-maintenance perennials. Regarding the direction of the parents, part of it is very high and then you have a steep slope according to the plan. I would use a high retaining wall there. You can execute it in one piece or with one or two steps. Definitely let it become overgrown so it doesn’t heat up so much in summer. At the bottom, you can still plan a seating area, pool, I don’t know.