How high does the house rise - how high to pile up earth (cellar depth low)?

This is really difficult. How high exactly above the current ground are the doors?

I just thought of that as the first option as well. You would just have to see if the balcony would then be so high that you can at least stand underneath it. Otherwise, probably rather pile up there, build walls around it (consider water drainage), and leave the rest at the [übriges Niveau].

What do you mean by "remaining level"? Something between terrace height and street level, or completely street level?

Because for exactly this reason, the development plan applies (or is it the state building code?)

I mean the current ground level (plus a little topsoil or paving stones at the entrance or similar) you also have to consider that your inspection shaft is at street level, if I see it correctly in the pictures

Then the basement would be almost completely exposed, except in the area of the terrace, it would practically be the ground floor. The rooms in the basement could have been equipped with large normal windows instead of the small light well windows – then there wouldn’t have been a need for the base color and a lot of exterior plaster is missing for this variant...