Expensive plot + single-family house 155 sqm + cellar KFW40+, financeable?

Hello,
you can see the rough key data above, thank you in advance for your help.

We have been offered a plot of land of 815 sqm for €250,000. That is €300 per sqm. The current standard land value is €260. The planned house is as mentioned above. It is a fully developed plot. The rough calculation with a general contractor here in the area resulted in about €317k for the land (including everything) and €418k for the house (€2400/sqm living space). It should be noted that the items kitchen, garden, and carport have already been included. However, the general contractor has also cleverly accounted for the loan forgiveness and the BAFA subsidy, so on top of the €735k, another good €40k will be needed, which must be provided. This is the first rough calculation. The first house design already suggested that the costs would probably not be that high. In addition, we plan to do smaller tasks ourselves. Construction would certainly start at the earliest in the middle of next year.
We are aware that this is a very high amount with relatively little equity. Our situation with currently one salary and, in the future, the mentioned collectively agreed salary increases must certainly be taken into account.

We would now like to know what your assessment is?

General information about you:

[*]How old are you? Both 35
[*]Are there children? 1 + 1 (from 04/21)
[*]Are children planned? see above
[*]What do you do professionally? both doctors
[*]currently one employed and one on parental leave until 04/22 (planned)
[*]How many hours do you work? one 40h/week

Income and expenditure totals:

[*]Total income €5000 (from mid-2022: €6200, with annual collectively agreed increases)
[*]Total expenses €3100 (including current rent), about €2600 at move-in (including building/homeowners’/elementary insurance, life insurance, calculated incidental costs €2.5/sqm living space, also we will cancel/change the gym and then be cheaper)
[*]Balance €1,900, later €3,100.

General information about the property:

[*]How large is the plot? 815 sqm
[*]What is the standard land value? €260
[*]New build, old building (year of construction), house type? KFW40+
[*]Garages? Carport
[*]How large is the house? (living space / usable space) 155 / cellar 70
[*]What is the market value of the plot and house after completion? I don’t know, how do I find that out?

Construction or purchase costs:

[*]Total costs (see above)

Cost breakdown:

[*]Total costs €775,000
[*]Deductible equity €140,000 (of course we do not want to use it all)
[*]Financing amount €675,000

I'm curious to hear what the others say.

You would actually think that two doctors can build a 160sqm house. We are building pretty much the same with an expensive plot of land as well.

Only what I don't understand: 1. Why is there still such a huge additional cost for the plot? 2. Why don't you want to use the 40k equity? Having a reserve of course does no harm, but 40k is already a lot given the "poor" equity basis. We will use almost all equity except for a high four-figure sum. We have also saved a bit more, which lowers our financing requirement. On the other hand, you will have a lot more room to increase your salary in the future and will probably laugh about a 2000€ monthly payment in 10 years.

Would it be an option to first buy the plot and save more equity? On the other hand, the plot price doesn't sound like a one-time bargain compared to the standard land value, does it?

1. Why does the plot cost so much extra?
2. Why don’t you want to use 40k equity?
Having a reserve certainly doesn’t hurt, but 40k with the "poor" equity base is already a lot. We will use almost all equity except for a high four-figure sum.
Would it be an option to first buy the plot and save up more equity afterwards?
On the other hand, the plot price compared to the land value guideline doesn’t sound like a one-time bargain, does it?

Regarding 1.) That includes additional costs, but also carport, garden, kitchen are included. Basically, the turnkey house is calculated for the house.
Regarding 2.) I assumed you’d rather have something in reserve. How much that should be, I really can’t assess.

Maybe for context again: I am a trained nurse, my wife initially studied something else, hence the late start into working life and the "low" equity associated with it.

We also considered buying the plot first and then building. In the end, we want to do it if it’s feasible. We will soon be 4 people and currently live on the 3rd floor without an elevator. You’d tend to move into a house or a big condo with a garden then and you’d pay about 1500€ here as well. That could also be paid off, I think.

Everyone in Germany seems to be looking for a bargain... ;-) ours (potential) plot isn’t one either.

The bank calculates with T€ 5. Of that, 50% goes for living expenses. Mathematically, €2,500 remain for other things. At least €2,000 installment. Retirement provision/insurances/cars/consumer loans...

From the bank's perspective, as far as I know, too tight.

My suggestion: buy land and pay down aggressively. Build and finance starting mid-2022 with a new salary.

How good is Ärzte und Apothekerbank actually when it comes to real estate financing?

I would also take a closer look at the cost side. I don't necessarily share the assessment that it will probably be cheaper in the case of Keller + Kfw 40. If you provide a more detailed calculation, we could see if anything is missing.