Floor plan of a single-family house on a slope with a basement

[*]Sliding door on the ground floor leads to the lower annex without an exit
[*]View only from the living room and dining area
[*]Dining area without garden access (see basement)

Basement:

[*]arbitrary window arrangement, also underground -> dining area with basement shaft -> exterior door under the dining area
[*]laundry room 30 sqm...

You can see yourself that your information from the development plan was incomplete and probably still is.

As already said, go to an architect to whom you can clearly explain what your wishes are. But please do not bring your plan.

Your property is a real challenge. Its requirements must be known along with the surroundings and the development plan. Without complete information, there is simply no proposal from me. I also know far too little about the state building regulations in your federal state.

You are the one who showers but doesn't want to get wet.

What do you think happens when we know where you are building?

Your floor plans are not worth improving. The architect should clarify the basics first.

Is there a soil survey from the creator of the development plan? Is the street already there?

A forum cannot replace the several-hour introductory meeting with the architect.

These are probably not even all of them, and I haven't even looked at the basement and terrain on the slope!

You start with the examination. Whoever comes first with the floor plans has no idea. The OP doesn't have to have that either. There are experienced architects who have studied it for years.

Is the point of reference specified? Or described in the development plan? As far as I know, it is in the middle of the property boundary on the street.

I would go as high as possible, unfortunately the connections just aren't there right now.

Is the reference point predetermined? Or described in the development plan? I know it as the middle of the property boundary at the street.

That's how it is, in post #18 exceptionally contributed meaningfully to own discussion:

The reference point is the green dot in the drawing.