Is the land use plan binding? Possibly a building window in forest area?!

I think you all believe that this is a plot of land on the edge of a settlement.

It is a plot on a street branching off from a densely built street that leads to other built-up streets. 500m to the local train station. 500m from the new development area (but in the other direction). Another 500-1000m from the town center (post office etc). On a large scale, though, definitely not sprawled...

All streets mentioned there are fully developed.

I think the plots on this street are/were (?) intended as green space/recreation, but due to the (admittedly very tense) land situation, they are increasingly being declared as building land (will be).

But, since it is too uncertain whether or when a permit will be granted, it’s out for us.

We are now at another plot Stam. Also no development plan, but according to the town hall definitely inner area and paragraph 34. Yeah!

On a large scale, however, definitely not sprawled...

You see, and opinions differ on that, especially if someone comes from NRW, where building plots often fall below the 200m² mark.
The plot is located in an approximately 5-hectare contiguous forest. The next house on the side street is about 160m away from the "densely built street" (in NRW one would speak of a loosened development). The following small group of houses is then followed by an undeveloped stretch of more than 120m. For me, no settlement structure is recognizable in the immediate vicinity.

admittedly very tense plot situation

Within the "densely" settled building blocks located in the somewhat more distant neighborhood, there are still many genuine building gaps, so this tension is not due to a lack of building plots but due to a lack of willingness to sell. And with that, the municipality's hands are tied, even if it wanted or could. Then it is almost impossible to get approval for further designation of building land from the superior authority. Which brings us to the instrument of the building obligation, which is suitable to cause great unrest and which no municipal employee willingly takes on.