Property / Development Plan / Retaining Walls / Excavations

It is also unfair in this regard because only the peripheral properties of the new development area are affected here.

And if I stick to it strictly, I only have 5m of space left behind the house and the retaining wall to be built (sloping property) would be about 1.70m, so also not allowed according to the development plan...

Another consideration. Take another plot of land.

For me, it is also a corner property, and would theoretically be 3.50 meters wide on both sides. Fortunately, all requirements were subsequently removed in the [b Plan] except for a hedge, which I can live with.

It is also unfair in this regard because only the peripheral plots of the new development area are affected here.

Well, what does unfair really mean? Don’t get me wrong, I understand your disappointment, but it’s not as if the development plan was kept secret and you were only informed after the purchase. Or was it? If not, these are simply the conditions on site; if you don’t like them, you’d have to resort to another plot or accept it as it is. It’s just difficult to tailor the development plan to all the individual wishes of a builder, right? We also have stupid things included, for example, mandatory shed roofs but with a maximum pitch of 16 degrees and roof tiles in red/brown tones. Aside from the fact that red roof tiles look totally crap on a Bauhaus-style house, the minimum standard roof pitch for roof tiles is 22 degrees. Ergo, we have to work with a costly roof construction in order to meet the tile condition at all. It annoys me immensely, but these are the demands of the development plan that I knew about and have to accept. And yes, I would definitely wish it were different...

The "prime pieces" in our development area are located on the edge of the field. It has been stipulated that a double-row hedge, a total of 5m deep(!), must be planted there as a boundary for the development area. This area has a value of well over €30K plus the costs for this hedge monster. The plots, of course, sold quickly anyway, but for me it was a matter of principle. Such nonsense. You don't have to go along with everything. ... in older plans, this green strip was still assigned to the city. Then some clever clogs apparently came up with the idea of selling the area along with the plots and immediately saving on operating costs :)

To the OP. If I were at your building authority, I would tell you. You simply have to build smaller, narrower, differently, then it will also work with the terrace and support angles, despite the edge strip which is just off-limits. It also lies outside the building window and would therefore be off-limits without conditions.
Conclusion, the property and the planned building are contradictory.
To Alex. What you are saying is outrageous. And I bet, in 2027 those hedges won't be there, and no one will care. Karsten