New semi-detached house - suggestions for the planned floor plan

One more step and at least 260mm stair tread are recommended. In my opinion, this is still feasible with the straight staircase. The staircase will then be about 50 cm longer.

However, it will then also be a different one (I could well imagine a standard model from this developer here, and that this is not negotiable at all). For the OP, the question would then be how much that bothers him; the house will not become unsellable because of it. I assume that he will not "grow old" in this house. Move-in of Mrs. Right, joint life planning, next house. I clearly do not see this as a house to fall in love with here (and if I were in the OP’s place, I would not be in a hurry to take the step into home ownership).

However, it will then also be a different one (I can well imagine a standard model of this developer here, and that it is not negotiable at all). For the OP, the question would then be how much that bothers him; the house will not become unsellable because of it. I assume that he will not "grow old" in the house. Move-in of Mrs. Right, joint life planning, next house. I clearly do not see a house to fall in love with here (and would not be in a hurry at the OP's place to make the step into homeownership).

Changing the staircase would cause significant additional costs. But thank you very much for the calculation.

I find the statement about growing old interesting. So, I turned 27 this year. My girlfriend can imagine moving in once I have settled in. But it is and remains my own project. Even if I do not want children, there would still be space in the house for a large children's room.

The fact that the plot is rather small is okay for me since the garden borders an undevelopable new orchard with a forest view (nature reserve). I have a flat area in front of and behind the house. I only want lawn and some paving.

By the way, the house will be built turnkey (only the kitchen and furniture are missing for moving in). House + land cost about €430,000 in total. After that, landscaping the garden and a photovoltaic system.