Land development / Is access via neighboring property conceivable?

If the neighbor is also the owner/seller of the property, then a right of way should be a matter of course. However, if he has nothing to do with the property, then you are more likely to have bad chances. Not only would the access road pass very close to his house, but he also won’t be exactly thrilled that a house is being built right in front of him to the southwest. Why would anyone agree to that? I would rather clarify this with the building authority. Unfortunately, the sketch is not suitable to give any profound advice.

The cutout is really inconvenient. As it looks, the property is far away from both roads. I would not agree to that as a neighbor. It would apparently run directly past his house. Having experienced in my family what kind of difficulties such constellations can cause, I would neither buy something like that nor agree as a neighbor.