Additional financing for real estate transfer tax

Everything has already been written! The OP does not understand the difference between external development and internal development. He might have paid for the external one almost like we all did with the property. But then there is also the internal development plus everything else you listed.

Hmm, by now he probably knows that. The problem is: if these costs are not considered, what other costs were not considered?
I really feel sorry about that now.
This behavior of ignoring or not responding anymore shows that he feels uncomfortable having to be told this here.

It's a pity that there is no "Dislike" button here, because many answers just sound arrogant and like a smartass. Only accusations instead of explaining properly what he needs to pay attention to, as if so little thought was given, as if one is born with this knowledge. That is exactly the reason why he doesn't respond and not because he is now sitting in a corner thinking: oh dear, what have I done....

It's a shame there is no "dislike" button here, because many answers just sound arrogant and like know-it-alls. Only accusations instead of explaining sensibly what to pay attention to, as if so little thought had been given, as if one is born with this knowledge. That's exactly the reason why he doesn't respond and not because he's now sitting in the corner thinking: oh dear, what have I done....

But now honestly - if I take out a loan of a quarter of a million, I have to carefully inform myself beforehand about what costs will come my way. For example, I only submitted my building application today after 2 years of research, planning, obtaining offers & coordinating with future neighbors in order to be 90% sure about my cost calculation. What are forums like this for? When it comes to TVs, cell phones and kitchens, people spend weeks and months reading up.

Of course you are right, but also consider that here a layperson is coming and truly seeking help. It's all about the tone, sentences like: well, good luck or you're going to have a lot of fun don’t help either, because you really feel like an idiot in the truest sense of the word. Do people like that? Rather not. Even if you now spent 2 years on the building permit, you will still make mistakes and regret them afterwards. We will all make these mistakes, no matter how well informed we are. Yes, this mistake by the OP could have been avoided, that is now clear to him as well, but the posts still sound somewhat "harsh" and indeed arrogant.

It's a pity there isn't a "Dislike" button here, because many answers just sound arrogant and like a smartass. Only accusations instead of properly explaining what he needs to pay attention to, as if no thought had been given and as if one is born with this knowledge. That's exactly why he isn't responding, and not because he's sitting in a corner thinking: oh dear, what have I done...

I see it the same way as Zaba12. When it comes to building, you really have to research and calculate carefully including a decent buffer, by now everyone really knows that. And once you've made that decision, you just go on the internet to look for lots of information. I didn’t know much about building either, but after two weeks of intensive reading, it quickly became clear to me that "the plot is fully developed" does not simply mean the house just needs to be set and everything is already connected. That a good buffer for groundwork is always included, what a linked transaction means for real estate transfer tax, etc. These are just basics.

And honestly, we're not in kindergarten where you have to carefully consider whether to tell Justus-Kevin that he put the building block together wrong. No one here took it personally. You can tolerate a “Well, have fun.” That shouldn’t throw you off your mental track now.

I see it like Zaba12. That when building something you have to research and calculate very precisely including a proper buffer, everyone knows that by now.

I also agreed with Zaba on that, that’s not what this is about, see above.

And honestly, we are not in kindergarten where you have to think carefully about whether to tell Justus-Kevin that he put the building block together wrong. No one took it personally here. You can take a "Well, have fun" comment. That shouldn’t throw you off mentally.

No one says he is psychologically devastated. I read through the posts and almost all of them came across as "clumsy and know-it-all" to me. My perception is that half of them could have been spared... like these posts, for example.

Have a nice day!