Removal of the crane on the sidewalk

That is almost childishly naive, sorry. In which industry does that happen?

I worked for a very long time in a research team at a university. In my estimation, almost without exception, everyone always gave their best. And I also get that impression from medical practices, for example (I am legally insured. ;-) ) "Actually" I can't think of any industry right now, except real estate agents, where this is not the case.

I can only urgently recommend to the OP to call the office and explain the situation.

Unfortunately, on the other hand, the office has already explained to him in writing that it is disappointed with the communication and the situation assessment of his agent of performance. It does know the situation. Or are you referring to the tear duct, that the OP would have a long journey to bring the train into the story himself? – then they will rightly be of the opinion that he must appoint a conscientious representative on site. Of course the king has a long journey if his bailiff is no good. But then he has to replace him. The building community cannot make up for it if an obligated person (after all, reasonable conditions) hides behind a pipe.

I worked for a very long time in a research team at a university. In my assessment, almost without exception, everyone always gave their best. And that is also the impression I have, for example, from medical practices (I am publicly insured. ;-) ) "Actually," I cannot think of an industry right now, except real estate agents, where that is not the case.

To stick with your analogy: the publicly insured is here the road safety in the construction street, and in the medical practice the builder doesn’t have a trained nurse draw the patient’s blood, but a real estate agent. It becomes so clear that this cannot be allowed to continue, and that the Association of Statutory Health Insurance Physicians ought actually to threaten Doctor Builder with revocation of his license?

During the construction of my house, I coordinated with the authorities early on, openly, cooperatively, and reliably, and I have no regrets. A spiteful neighbor filed lawsuits against me at the district office every week, all of which were immediately dismissed, but sometimes an inspector was on the construction site - he measured everything, confirmed its correctness, and also dismissed the neighbor's last lawsuit. Every office had our phone number, and in the municipality, it was known that one call to us was enough and things would be taken care of. That proved to be effective.

We often dealt with the municipality, for example regarding the crane but also trivial matters like a portable toilet that had to be moved by 1 meter. I have to say: I am the builder, I take responsibility first. Of course, I have the general contractor, but it is truly in my interest to keep an eye on things every single day to make sure he doesn’t do anything wrong. It could be construction defects, it could be a misinterpretation of the requirements, anything. It is in my very own interest to ensure that none of that happens.

Sorry, but anyone who cannot or does not want to supervise their construction is better off buying an existing property.

I worked for a very long time in a research team at a university. In my assessment, almost everyone always gave their best there. And I have a similar impression of medical practices, for example (I have statutory health insurance. ;-) ) "Actually," I can't think of any industry right now, except real estate agents, where that's not the case.

I also know the biotope "research at the university." It has nothing to do with real life. There are people who have chosen a job where you work 50+ hours but only get paid for 20. Of course, they are really good and motivated, otherwise they wouldn't be there. I don't know why you haven't noticed this with medical assistants yet, but at the latest when you commission craftsmen or go through a change of caseworker at authorities, you notice that competence is a very unevenly distributed commodity. And zeal, too.

Sorry, but anyone who cannot and/or does not want to supervise their construction is better off buying an existing property.

Well, yes and no, the OP and his buddy did do that, and it was a single-family house on a plot suitable for a semi-detached house, after all, that’s the kind of building plot they were looking for. In my opinion, the essential fundamental mistake they made was to imagine the developed plot as already successfully and uncomplicatedly leveled as a finished building site, which does not correspond to reality here. In continued naivety, they then put their trust in a construction entrepreneur who presented himself as competent for this. A freelance architect could have recognized in time that this self-assessment is untenable given the complicated situation. And I could have given the OP more warnings earlier if he hadn’t only revealed little by little the reckless mission he was planning. To recall: the question was originally about converting the existing garage. Only the desire for a semi-detached house was announced. I only learned about the madness of a deep demolition next to a neighboring house attached at the border when it was already underway, secondly when the incompetence of the site manager became evident, and first when the OP revealed that he had embarked on the project without a self-appointed freelance architect. The OP was essentially sleeping with rose-colored glasses until the crumbling of the sidewalk woke him up, oh no, what am I saying: “put him into a half-sleep.” He still hopes that the choice of contractor was just a bad dream that can be chased away by singing “Heile, heile Gänschen.” No amount of Doornkaat can I drink that wouldn’t give me back pain just from reading about it ;-) I cannot imagine a construction site where a retired civil engineer cannot be found nearby who would, for a little side recognition, serve as a value-added webcam alarm if nothing is being done except playing in the sandbox.

We were always available as contact persons for all topics but avoided giving the impression that we were controlling anything

Well, actually it's not even about control, but about communication, contact persons, and interest in the ongoing house construction. You can't just enter the house construction as an appointment for Monday and Thursday – house construction feels like an annual event. If you find gaps for other nice things, that's good, but the calendar and mind should be occupied with house construction.

My husband and/or I were also regularly on the construction site, but "actually" only to refill drinks, food, etc.

This, for example, is a good indication of what you do instead of "control." Gaining an overview in the process then comes naturally. After all, you yourself are the builder – not the civil engineer and not the general contractor.