Floor plan of a single-family house approximately 150-160 sqm on a 480 sqm plot in Middle Franconia

With a basement, that’s probably 240 sqm, plus a fireplace, pellet heating, etc.
500,000 won’t be enough for that.
Children’s rooms are very small compared to your bedroom.

4 boxes = 1 m? Then the staircase with 300 cm is far too short


Stair lengths with floor heights of 280 cm, which is not very high nowadays and leads to rooms with a maximum height of 250 cm. Today, floor heights from 290 to 305 cm are more common.
The left staircase would be very comfortable to use, the right staircase would be standard.

The doors with a rough opening of 75 cm would also be far too narrow on the 1st floor.

Thank you very much for the prompt feedback! I will read it carefully this evening / over the weekend and incorporate it into the plans. Regarding the OG: I am also not happy with the room layout yet, but somehow I lack a good idea of how we could do it fundamentally differently if all the rooms are oriented to the south and the long staircase is on the north side.

and the long staircase in the north.

Oh, so the floor plans are faded ...

Oh, so the floor plans have been rotated ...

Sure, do you know it any other way? So that they can be rotated to match the site plan.

Sure, do you know it differently? So that they can be rotated to fit the site plan.

Especially so that they fit on an A4 sheet ;-) That's why both floor plans also have a north arrow