House price way too expensive? Experiences?

Do 15 years, put a bow on it, forget it. Book the installments as rent and secretly be glad that you are not a tenant.

One could still ask whether 206 m² of living space is necessary or if ~170 m² would suffice. That should lower the price.

170 would be enough for me, but the developer builds the house like all the others in the development area. Unfortunately, there is nothing to be done about that....

I think it's good to have 1-2 additional rooms; especially when there is no basement.

There is a basement, right? It just hasn't been counted yet for the 206m². In any case, it's amazing what a) you pay for a piece of grass and b) what a house costs nowadays. Nowadays, €250k is already considered a bargain.

Yes, Keller is included....