Selling new construction after receiving funding / Wohnriester - possible?

I wouldn’t hesitate for long if the situation doesn’t improve for you. You can just leave a mis-purchased sweater in the closet; that doesn’t cause any further issues. A “mis-purchased” house is best undone by continuing to look around. I wouldn’t find that bad at all. I didn’t find it bad for myself either.

For me, it happened that from the unavoidable annoyance of my downstairs neighbors, the thought crept in that I wanted to move out of the apartment. At first, the thought wasn’t very explicit or clear to me; I was more thinking about the question of how I could work more at home or nearby. Then I came across a mid-terrace house from a developer that was already at the shell stage.
And so within half a day, I made the decision that I wanted to buy the house, then spent 2 more days on banking matters (later spent a few more days on that as well), and voilà, the decision was done.

I do understand the lack of understanding from those around me, but that simply isn’t important.
Look at your finances, what does your husband say when you talk about selling? Then you can see for yourself if it feels right or not.

It’s not certain at all that you will make a loss. And if you did, I wouldn’t care because hopefully something positive stands against the loss. So the idea that making a loss is a stigma to be avoided is nonsense. Just think ahead mentally and together with your husband. Then you’ll see what it means for you.

What could the walls be made of? I think a brick wall looks nice (visually), but it is neither particularly massive nor particularly cheap.

Ask experts. There are definitely companies that specialize in that and can assure you of wall xy things. They will come by and take a look at everything.

What I don’t understand is why you didn’t inquire at the appropriate places about the cost. But you are not asking in the right places here. A phone call would have helped more than all the accusations here.

What could the walls be made of? I find a brick wall nice (visually), but it is neither particularly massive nor particularly inexpensive.

How about calcium silicate brick with little hollow space? You can put a layer of bricks in front of it for the look. But better than the bricks, there should be tall plants there that grow higher than the 2m wall.

So if my wife was crying because of music from the neighbors, I would have already gone to the neighbors and talked to them. Without accusations, simply describing the situation factually and asking for consideration. An attempt to set some boundaries. The other thing can still be tried as well.

"oh look, the neighbors are also listening to music on the terrace. It is socially acceptable to do that." , or something like that.

But you have to do it at socially unacceptable times too, it has to annoy him like he annoys you. A mini-Alexa won’t help with that either.

We also had a problem with the neighbor’s son who often came home around 10 p.m. on his tuned dirt bike, rode between the house walls, and then revved the engine a few times; sometimes the kids woke up. I talked to him and his parents, it didn’t help. Eventually, I had enough too. So, on a few Saturdays, I let the excavator run in front of their bedroom (6 a.m.) and had breakfast first. It didn’t take long before the old man asked what that was about. I explained the problem to him again in detail. Since then, the son pushes the last stretch or coasts with the engine off when he comes home after 8. Works fine....

Before I sell, I would try a few things if I were you. A lot has already been said. Have someone knowledgeable take a look, look for a factual conversation, just annoy him (more strongly) yourself sometimes. Maybe he’ll figure it out on his own.