City villa 200 sqm + spacious double garage planned in Saarland

So far, only complaints have been made, but no concrete counterproposal in the form of a sketch. What do you mean by 3.5-4m wall? The height? You are far off with that.

You are aware that the wall to the neighbor, shown in the picture as about 60-70cm, is actually 1.50 - 1.80m high? This view is then somewhat too optimistic...

If the neighbor's garden on the left side is not nice, just make a planting strip there and a nice hedge.

I quote the post from RomeoZwo. The garage stands directly on the wall, and that at a 3.5-4m distance from your house.

Have you ever seen a plan with elevations on which the house + garage are drawn on the plot?

So far, there have only been complaints but no concrete counterproposal in the form of a sketch.

That's what architects are for. Real ones – meaning those with a degree and interest in the project.
Once again, typical men's plan: the main thing is that the garage is big enough and optimally placed. This one immediately comes to mind again:

The floor plan by itself is not bad, a few minor points could be discussed or have already been discussed. For example, a door from the utility room to the kitchen for use as a storage room for drinks or a freezer, etc. Overall, a lot of space is lost to the corridor on the upper floor, but I personally like that. It is perfect as a photo gallery. So actually no disadvantage, especially since the room sizes on the upper floor are fine due to the large floor area of the house. ("large" for me, our house is almost one meter shorter in every direction...)

And here we come to the main problem: you don’t want to hear it, but I am closer to you than you think. Rather a small plot of land and unfavorable north orientation, we could have built bigger (site coverage ratio, building boundaries, etc. all still with room to grow), but we didn't want to cover everything with buildings. You would gain more quality of life from a more airy garden and a different arrangement than you would lose from downsizing and for example mirroring the house. And: the savings in house size can flow 1:1 into the equipment. If we had built bigger, my wife definitely wouldn’t have been able to order 120x60 cm tiles for the bathroom anymore.

I think the one there is meant. I believe in the animation the sun is at north-northwest. Around early afternoon

What are those geographic coordinates?

and, the sketch is incorrect. In order for the garage to remain usable (driveable), its finished floor level must be somewhere at a maximum of 101.5m. That means the finished floor level in the house (due to direct access) will be similarly set, but the boundary lies on average at about 103.2, meaning the wall at the boundary must be 1.70m high. In the 3D visualization, it is at most half as high. For comparison: window sill height ~0.9m, the wall is even depicted lower.

And on this 1.70m high wall the garage then stands. It has all been said already, but that is an unpleasant backyard and not an inviting terrace.

Now one might say, it can be buttressed (not a good idea toward the house, but be that as it may), the height difference does not get any smaller.

In order to achieve the condition as shown in the 3D animation, the house must be set at about 102.5m finished floor level. But that would be way too high for the garage and also way too high for the walkway: 2m above the walkway at a distance of 2.3m is also rubbish.