Yes, I think we agreed on something that everyone can live with, although I do assume that we accommodated him a bit too much.
Each of us pays for one of the two additional L-bricks (i.e. 2 meters) on his garage side wall.
He showed us an initial architect's draft that depicted both garages ending at the same "depth" at the back (due to different house lengths, garage positions, and garage lengths).
During the approximately 9-month planning phase, this status became "irrelevant" for us and him after about 3 months due to replanning...
and long before the garage order and excavation work, it was clear and known that his garage ends about 2 meters further back in the ground than ours.
Ultimately, it is all a communication problem, especially I am disappointed with the architect, as he never informed us of this or showed in later plans that the two houses are not on the same "line"... and thus the garages are offset at the back with the now disputed consequence....