Overall I can respect this opinion. I have a few comments, though.
Not sure how the path would have disappeared in two years. To me that notion is at least somewhat improbable.
I feel bad about about drawing this card again, because I feel like it sounds made up. But, I do know people, both OSM contributors and others who have either walked or observed the path within the last six months.
My in-laws have hiked there; they live not too far away. And I know @Vegard_Engen would probably vouch for the paths existence wholeheartedly. From what I understand he is also a neighbour. This makes him as attached to the case as they are, but that is not true for my in-laws.
I’d be interested to hear whether that changes your perspective.
I agree on the first reason not being valid, but I do think that a survey done by property owners should be taken with a grain of salt when said survey conveniently fits with their stated interests. At least until they are documented by visual evidence. Thus far I’m the only one who has posted visual evidence. They have not.
Your drawing contains two (easy to make) misunderstandings of pretty big significance. The building in the top right is a garage and thus has no 20m zone. You have to measure from the residential unit on the plot. Also, the “private zone” isn’t ever allowed to cross property boundaries. If it’s 2 meters from your wall to the boundary that is still where your private zone stops. Unconditionally. Hence, you can leave out the zone coming from the bottom of the image, as there is no uncertainty regarding the path being outside of it. I’ll point you to documentation justifying these changes if you feel you need it.
If you make those changes, at least in my opinion, very little doubt is left. But, I have a bias here as well, so don’t take my word for it.