Yes, like that too! Where in Essen are you stationed? Last year, we practically acquired a little house in Kupferdreh under the radar. The renovation is in planning. We were just lucky. I find new construction even more difficult around here. With real new development areas, I generally find the end result alarming, and prime plots are unaffordable. Recently, I saw something for over a thousand euros per square meter, mid-range location in Heisingen.
We are currently in Holsterhausen but have searched for existing houses and plots of land in Essen, Mülheim, Duisburg, and the Mettmann district (workplaces for me and my wife in Düsseldorf). Indeed, there are only very few plots available on the open market. However, we did not apply the Barthel tips, so I don't know how much is sold under the radar.
We were lucky and got a plot in a new development area in southern Duisburg for 720€/sqm, but unfortunately everything else is far from cheap. There is a very restrictive design statute there, which, however, matches our ideas, so it is not a problem for us.