Double garage boundary construction in Bavaria

In the variant with a 3m distance, we would like to have access from the upper floor of the house to the garage; is that possible considering the house wall height of 6m? Use as living space will probably be difficult.

To answer that, more information is needed than a simple 2D plan.
We basically know nothing about the house – only the shape and that there is a double garage on the left side of the plan.
Single or two-story, roof pitch, floor plan…
Living space excludes boundary construction.
And whether it makes sense to include or exclude the garage in the thermal envelope cannot really be said here without everything.

But this piecemeal tactic also makes one very tired.

We don't have a floor plan yet. Just a template from the internet that matches our ideas.

The terrace will probably be planned around the corner facing southwest