Single-family house south slope - floor plan planning, tips?

Without measurements, assessment is almost impossible. The quality of your information is really poor. Sorry. I only see that the guest bathroom is terribly laid out. I count 250 sqm including the basement but without the attic. For office spaces and kitchen, I assume that unfortunately you have to apply prices for "normal" living space. You may not be aware of it yet, but this will blow the architect's estimate out of the water, and not by a little. And even if you only want the floor plan to be evaluated, it only makes sense to evaluate floor plans if they are also financially feasible. If you have an additional €100k beyond the architect’s estimate, many will gladly continue here.

You have a difficult hillside property and want to build 3 floors. That is not something for an amateur, trust me.

The architect prepares a floor plan, which you have to pay for anyway in Germany. Therefore, there is no need to torture yourself with it. Just write down in text form what you need, bring a site plan of your property (with elevation figures), and find a professional you trust.

Come back with the result, and then we will gladly optimize the details with you. But the rough plan must come from the architect. Everything else is not worth discussing, given the size of the construction site.

Go to the architect.
Utility room through pantry, pantry as a passage room, ... to the bathroom, every observer can see that something is wrong there.

Fängt man bei der Grundrissplanung im EG an?

Was sagt denn das Forum dazu?

Anyone asking these questions should definitely hire an architect for a project costing around/more than €500,000 during the planning phase. In my opinion, indispensable for a slope. It’s not supposed to be a standard 4-room house.

der Vorteil läge darin, dass Mama & Papa unten kochen und die Kids oben spielen

man kann von unten nach oben rufen, dass das Essen auf dem Tisch steht

You are only thinking in the here and now… what if Mom & Dad become “the elderly” and the kids become fledgling teenagers who only come home with their friends at 10 p.m. and want to eat pizza (without the elderly)

Kann mir das Forum bitte Feedback geben zu dem Grundriss, damit ich ihn optimieren kann, bevor ich mich an OG und Keller mache.

see above.
Yes, and without dimensions: it’s like eating chips without using your hands.

I also don't understand this cozy corner. How are 5 people supposed to fit in there and where is the TV supposed to go? The narrow bathroom has already been mentioned.

In addition to what has already been noted, I also find the "all-purpose room" difficult to furnish. The kitchen is hard to set up because of the protruding staircase. Or do you really want the outdated L-shape as drawn so far. You have 45 sqm of all-purpose room. That’s not so little. But you don’t have a spacious, easy-to-furnish kitchen, zero space/wall area for a shelf or sideboard or the like, no couch space for 5 people, and the TV position is questionable. Only the dining table is nicely placed in the room with a view of the stove. So for me, that’s 4 negative points to 1 positive point. So still very much in need of improvement.

Clearly an architect

Guest bathroom doesn't work

This cozy corner belongs in the chill lounge and does not replace a living room for a family of five. The children grow up

The staircase separates the kitchen inconveniently.

Pantry as a walk-through room is not acceptable.

You are planning a huge house. And yet there is a lack of reasonable rooms.

Before you go to the architect you have to massively increase your budget or build smaller.