Height reference point boundary construction Brandenburg

Tell me how to find the development plan online. Not a link, but what Google needs to display a result.

The development plan says nothing about this. Neither in the image nor in the text section. I am aware that the boundary development concerns the average wall height, since it will be a garage with a flat roof, I simply referred to the building height as 3m. Sorry if that was misleading. The development plan with all additional documents can be found on Google using the search term: Bebauungsplan Luckau Herzberger Straße There is no significant slope in the area. I already sent a preliminary inquiry to the building authority by email yesterday. Thanks in advance for the lively participation.

“Funfact” on the side: The bottom edge of the perimeter insulation of the house's floor slab is at 78.06m. Only a 1m passage is planned between the house and the garage, as the garage is supposed to be set back somewhat compared to the house and will only really stand next to the house in the rear area. With the garage floor and driveway at 77.93m, our driveway lies so low that it is beneath the soil under the floor slab. I still lack the imagination for how I can “cover” this without further reducing the tight 1m distance... When you think you've thought of everything… but well, at least our architect only now comes up with this during the preliminary planning; at the start of the construction project, these facts were not yet relevant - luckily the house’s floor slab was concreted last week… (irony off)

Turning off emotions again doesn't help now. If anyone has a sensible idea how I can save/cover up this faux pas, I would be happy to receive suggestions. I have a meeting with the architect on Monday; he will surely have one or two sensible ideas as well. And who knows, maybe the [Bauamt] will answer me quite unexpectedly that the natural ground level is not the relevant reference point after all, but some other one that is higher.

Turn off emotions again, it's no use now.
If anyone has a sensible idea on how I can fix/cover up this faux pas, I would appreciate suggestions. I have a meeting with the architect on Monday; he will surely have one or two sensible ideas as well.
And who knows, maybe the building authority will unexpectedly reply that the natural ground level is not the relevant reference point after all, but some other one that is higher.

We are facing a similar problem. How did it turn out for you?