Is a house for a total volume of 400k still possible at all?

But a small house without a basement :)

You can "forget" the basement from the start and for example with bigger windows, a lift-and-slide door, [Raffstores], a fireplace and large/good tiles also reach the 400k€. You have to consider that many here write 2200€/sqm without incidental building costs on the price. With that, you are already 10k€ over your self-imposed limit. Besides, you need a buffer for the foundation and other stuff you are currently not thinking about. Therefore, I say, don't be surprised if in the end it turns out to be more!

Actually, without a basement it was not an option to start the whole thing so far. Now we will reconsider whether we will actually take the opportunity. If the real estate market possibly crashes soon, the value may no longer be as high as the remaining debt. Still, thank you and stay healthy :)

Don't believe that the market will collapse, at least not for long. There is a need for space, especially now the advantages of the garden are becoming apparent. A 90 sqm apartment with a smoker's area causes difficulties that you don't have with 120 sqm and a small garden.

Actually, without a basement it was no option to even start the whole thing so far. Now we will think again whether we will really take the opportunity. If the real estate market possibly collapses soon, the equivalent value will no longer be as high as the remaining debt. Still, thank you and stay healthy :)

First, consider what a basement is actually needed and used for. Usually, people have their own barrier in their minds.
As if you only build a house to have a basement.
Actually, you build a house to live somewhat more self-sufficiently and to have a garden. Whether with a basement or not.
Maybe you should read up a bit in the forum regarding "basement or not" – there are enough discussions here that could help break down the mental barrier ;)

hm so we have already given it some thought. The following points are at the top for the basement:

Laundry room for washing machine and drying room
Utility room not on the ground floor
Hobby basement (workshop)
Hobby basement multimedia

I see it as almost impossible to accommodate all this in a 125sqm house without a basement. It must also be said that we are a household of three. Well, as I said, we will now first think about how sensible the whole thing is.