Floor plans of a single-family house with a granny flat, 280 m2 on a pleasantly small 320 m2 plot

ah, recognized correctly. The way you responded to criticism seemed familiar to me.

Aha. And if they had brought in a professional right away back then, they would have easily saved 100k€.

ah, richtig erkannt. Mir kam die Art, auf Kritik zu antworten, bekannt vor.

You can also see how the prices have developed. One should have just built at the beginning of 2021 – at that time, the price estimate for the house was still €640k from the planner. Now it's (I usually don't participate in floor plan discussions, but the house with a granny flat doesn't appeal to me at all when I want to build my dream house) already €1,000k. So, 2 years of planning just happened to cost as much as a second small house in the countryside. Sometimes you plan yourself to death – not to mention the new financing...

And here again my quick suggestion based on Katja's basement (window slightly modified, because that is allowed) .... although I wonder how the parking spaces are accessed ...

I am also donating views (no pointed roof due to time constraints)

I have the feeling that the OP does not want to hear any criticism, but a few comments on the floor plan. Bathtub in the ground floor bathroom, where normally the guest bathroom is, why? If you want to take a relaxing bath, do you want to walk through the hallway in front of the front door? In a narrow bathroom with only a small window? And the kitchen, it has little storage and workspace for four people and no serious storage room. (Unless the basement apartment is never an ancillary apartment, but a questionable home office commercial use where you can easily set up storage rooms, which is why you don't need storage space upstairs,... then you don't need to discuss floor plans that are just for the building authority.) Why is there another office on the ground floor? You are building almost 300 sqm and have space like in an apartment? Just to finance the construction through rental income via your wife's club?

You can also see how the prices have developed. One should have simply built at the beginning of 2021 – the price estimate for the cabin was still €640k from the planner then. Now it is (I usually don’t participate in floor plan discussions, but the house with a granny flat does not appeal to me at all if I want to build my dream house) already €1,000k.

So 2 years of planning have just cost the price of a second small house in the countryside. Sometimes you plan yourself to death – not to mention the new financing...

Woulda coulda shoulda :-) So many things have happened that you have no influence over.