Hello,

there is (still) no tag for such areas in OSM. But you could invent a new tag, for example "boundary=land_and_parking_service" + name tag. Then there are no conflicts with the administrative boundaries.

I will restore the original administrative boundaries and leave and retag the two existing segments to the north and south. I can also try to restore the previous long segments. Is this okay?

Then, when the new boundary is complete, it must form a closed ring (not multiple segments).