What budget / financing is possible?

If you have too much disposable income, I would rather invest in faster repayment than in unnecessary square meters, or even gild the water tap for the washing machine.

If you have too much disposable income, I would rather invest in faster repayment than in superfluous square meters, or even gild the faucet of the washing machine.

That would also be my preference. If I am completely honest with myself, the following is sufficient for us: 500-600 sqm plot (costs between 80k and 140k depending on location here) 140-160 sqm living space without basement Must haves: open living / dining / kitchen area with small air space and gallery, dressing room and 2 offices, real wood flooring, minimum KW 40 plus garage That should be doable with all in 550k and 1700-2000 € repayment? Then there is still enough money for a bit of luxury and a winter residence in the Canaries in old age :-)

If I'm completely honest with myself, this is enough for us: 500-600 sqm plot (costs between 80k and 140k here depending on location) 140-160 sqm living space without basement Must haves: open living / dining / kitchen area with small air space and gallery, dressing room and 2 offices, real wood flooring, minimum KfW 40 plus Garage

Well, plot: even though I like to be modest when it comes to the house itself, I would still prefer more than the usual three meters of walking space between house and fence for the plot. Even a small dog enjoys a large garden. With 600 to 160 sqm you are already above where the average builder squeezes in. KfW40 is, in my opinion, gimmicky. Especially with a comfortable disposable income, I would like to be able to change things quickly and not do anything that, to put it kindly, “pays off” only in the long run. A gallery - what for? - if you don’t have children, you don’t need a pulpit from which to deliver the curtain lectures ;-)

The topic of children has already been mentioned. It is really important that you clarify that. A year ago, I also wouldn’t have thought that something would come up with us, and my girlfriend was already 40 then ;)
And instead of starting with a square meter size, I would first go through which rooms you need and how big they have to be. Then think critically again about whether that all makes sense, for example, a sauna in the basement also means a lot of moisture down there. Under certain circumstances, it is cheaper to move something like that to the garden, then you also have the cooling off directly in winter when you come out.

As far as finances are concerned, I would proceed exactly the opposite way. Consider a monthly payment and determine the total budget backwards with a certain repayment period. Then see whether that is also realistic for the bank. Of course, the bank wants to finance as much as possible, but this approach has the advantage that you may not exhaust the maximum budget and, if in doubt, can still increase the budget if costs rise due to the soil survey or if the wishes in the planning turn out to be too big.

No, I certainly won't work there for 30 years, but in my industry within a radius of 250 km there are at most 5 people who can offer what I do. In the country where I work, there are 3 other facilities that have an eye on me and can offer me similar or better positions.

No idea what you do, but no one is irreplaceable. The wind can turn again at some point. Life is full of positive as well as negative surprises. Therefore, I think it's good that you are approaching it more realistically and not trying to exhaust the maximum budget right away. I also like the suggestion of quick repayment. Is land really available at the price you mentioned? Are the stated prices for plots of land that you find nice and usable, or rather "leftovers" that nobody wants? Depending on the region, the issue of land is very difficult and very expensive if you really want something usable.

The topic of children has already been addressed. It is really important that you clarify that.

Not at all, I had already included that in the advice on flexibility orientation: build what you need now, and if offspring come along, there will simply be the next house. That is the freedom for which I think a salary that enables rapid repayment is better used than preparing a floor with its own bathroom for children you don’t want to put in the oven within the next ten years ;-)