@ ypg my garden is not that flat.
You are at a height and your parents are in the depth. You should have considered the two properties together. The problem could have been defused.
Where the trash can is, I would have planned the path. (we don’t have one because walls were already there with us and there is a public staircase. It is missing)
Where bushes/privacy screen are, I would plan it as an L and absorb the 50 cm height difference there. That’s also a nice working height.
Down at the street around 222.40 m, I would plan a shared garden with the parents. Seating area, garden dike, sandbox etc. The relationship can’t be bad and I can imagine that a large shared area makes everything seem much more spacious.
You have from the top edge of the floor slab 222.40 with terrace floor 225.2 m 2.8 m height difference + the meter (just read 3 m) from your parents, that’s 6.8 m + fall protection, heavy wall. (The ones in the picture from yesterday by me are about 3 m) Why didn’t you coordinate better there?