Thank you for the answers. Regarding point 2, the last sentence, I share the same opinion. And I'll put it this way, the comments confirmed to me that I should rather keep looking :D. I'm more wondering why the municipality is planning such a new development area.
The demand is probably high and there is nothing better available for the municipality. Near us, there were also building plots, of 4 one was extremely hq. Additionally, in the entire area, seam rock (?) was suspected. 2 of the plots were sold by highest bid. Then a plot was sold privately here. Actually idyllically located, but so unfortunate that you can really hear the highway extremely. Someone must have bought it. Nearby (same noise level) someone said to sell by highest bid. That will probably go as well.