Your opinion / Construction costs of single-family house + granny flat in attic and basement

Project: Single-family house according to Kfw70 - 55 standard Windows triple glazing (aluminum-wood) Underfloor heating / also granny flat in the basement Basement with white tank Groundwater heat pump House ventilation with heat recovery Solid construction brick 24 + 18 WDM Living area 2 VG 200m² + basement 95 m² (including granny flat or fitness room) Wood stove in the living room Double garage 56 m² Asynchronous gable roof (large roof area facing south) Sauna / kitchen / parts of the outdoor area are included. Share of built-in furniture 15K The planning, construction management + tendering / and supervision are done by the architect. The whole thing should cost approx. 530 K Architect fees incl. 37 K Structural engineer 7 k I would appreciate your opinion.

Is the price-performance ratio reasonable?
I am happy about any answer .... :)

too bad that no one comments on this ;(

Since no one here knows what the property looks like, and whether you, let’s say exaggerating: want golden faucets, no one will be able to comment.

530,000 sounds like a lot of money, but if I now see that our much smaller construction project without a basement will exceed €300,000, I’m not sure if what you are planning can fit.
A basement alone can cost €50,000 and more, the garage will cost you about €20,000.

Sauna/kitchen/outdoor area only €15,000? Something like that costs a good kitchen. The outdoor area can easily cost €10,000, sauna... well, they don’t cost the world anymore nowadays :D

What else should one write?

Hmm .. yeah, sure, that's true.

It's not a First Class setup --> but it should be something decent.

and golden taps aren't included either .. (not yet). :)

In the calculation everything is fixed and fully accounted for --> so the basement is completely finished at this price.

I'm asking because of experience/opinion from others since I'm a bit unsure myself --> as you also noticed, this is about a lot of money.

Best regards