I am always shocked by how much space is sealed over for cars in the form of garages and parking areas. This is explicitly NOT a reproach against and his completely understandable ideas. It simply shows that price pressure per square meter leads to such small plots for single-family houses that nothing is left for proper water management and a pleasant microclimate. I do not exclude myself from this madness either; objectively speaking, I have too many cars myself.
I do not understand your post at all. Of course, it depends on the builder and his wishes to plan an exaggerated or necessary wide driveway. Usually, you do not need a double garage, and you also do not need a driveway paved across its entire width for living purposes. I know you're talking about plot sizes, but 550 sqm is not little either in most urban areas or at least near a community. If every builder had such a plot like yours, there would be no nature left to enjoy because everything would be fragmented and, on top of that, developed.
Basically, the desire for a double garage should be put under scrutiny. Is the space really needed, or is one just triggered by glossy pictures? A driveway to a garage also does not have to be 6 meters wide. At least it does not have to be straight. Anyway,
However, in Lower Saxony, you are only allowed to build on the boundary if the ancillary building has a maximum of 36 sqm.
6 x 8, 7 x 8... all are larger than 36 sqm. That is the difference from a free plot, where you have more freedoms or can also build, as mentioned. For us, except for the terrace and the house/garage itself, nothing is sealed: the driveway and the paths around the house are gravelled, the caravan also stood on gravel, the motorhome was also on the driveway when it was being packed. The neighbors do the same with their third vehicles or trailers: quite appropriately driving and parking around on the driveway. But from the sketch, it looks good. As long as nothing is built against the development plan, which was unknown here, as far as I remember. I have it myself, but I lack the patience to study someone else's development plan. The parking situation for possible visitors can be found here in the neighborhood: opposite is a sports field; one can surely find a parking space for a birthday visit. But let it be said: eventualities or rare cases cannot always be taken into account. In a new development area you are more restricted than on a free plot. You have to accept that for yourself if you intend to build there. And campers also know where to store their single-axle trailer. Usually, there is a neighboring campsite where one can nicely ask.
The problem I actually see is the tall tree stock, which is probably also responsible for the recessed building line.