Final construction of the access road, how far is the municipality allowed to go?

Your property must have a boundary. It is normally fixed with survey points. This should then also be the basis for your house. From the boundary, the municipality must involve you in the execution.

Is paving going to be done? Then an additional build-up height of about 10-12 cm will be added. That is usually "compensated for," just like now, right?! It seems to me that you have claimed the bend for your slope, where there is normally a straight property boundary line?

The embankment along the road is natural soil; only the gravel for the future driveway has been laid on it in advance, which I will, of course, still properly secure and retain in the upper area once I know the final road height. Otherwise, nothing was filled in by us. The building plot boundary basically ends along the gravel at the embankment. My question was also only about the fact that if the embankment is excavated because, for example, a sidewalk is planned there, which is still uncertain, and the embankment angle is not sufficient, who would then have to secure that stuff in the lower area up to the final road. Hopefully, I will know more tomorrow, as there is a municipal meeting on the topic of road expansion.

Your question can only be answered if you respond to follow-up questions. So where exactly is your property boundary? The height difference is rather in the decimeter range. So the sidewalk is easy to construct. Would the sidewalk be built on your property? That might require expropriation if you do not sell the land. That could take time.

The gravel/embankment start is basically the end of the building window, and then there are 3m left to the property boundary. Unless the surveyor has set the stakes incorrectly. I still have to look for boundary stones to the street (or I only have one). Final measurement still has to be done anyway, then I'll have the boundary points marked again.

So it is only a matter of what happens if the embankment, which lies 100% on your property, is damaged during the road construction work? Then my expectation would be that it would be repaired.