Boundary construction garage at another corner of the property

oh dear - no that's nothing.

Why not push the house as an angle into the northwest corner, the garage on the southwest border - so attach it to the neighbor’s garage - with the strip of land in the south you’re only doing the neighbor a favor, but you get nothing from it.... -

the floor plan also doesn’t fit the location at all...

If the neighbor is standing in his driveway, maneuvering out of the garage becomes sporty again. You don’t get visitors? Or do they always have to park in front of the garage?

the alternative would be as follows:

But what if the neighbor to the south builds a 10-meter-high palace directly on his north side? That would completely shade my south garden.
Here is an excerpt from the development plan: "
The maximum permissible building height is limited to 18.5 m above NHN. That corresponds
to an absolute building height of approximately 10 m."

Can someone explain to me what this means? What is the maximum building height now, 18.5 m or 10 m? Even if it is "only" 10 m, that can already be enough to cause the garden to disappear in the shade in the alternative arrangement

He is not even allowed to place his palace right on the property boundary.
You will also be the first to have no sun on your property - especially in the south, it stands very high / highest and already creeps over tall roofs in May.
There are plenty of plants for partial shade and too much sun only burns the lawn.
What I want to say with this: don’t just limit the garden to the south side and don’t see everything negatively... so far I only see that _you_ are placing a huge block right in front of someone's nose.

Then you no longer have a south garden

.....
What I want to say with that: don't just reduce the garden to the south side and don't see everything negatively...