If the property is sold, the probability of a reallocation is 99%. But that then is irrelevant for the OP. If he does not sell, then his land will be excluded from the development and marketing.
Both assumptions are wrong. Once a development plan preparation is decided, a reallocation procedure will take place without voluntary participation, provided it is necessary for the purpose of the measure. It would only be excludable if it could be left out when delimiting the planning area.
If you or the municipality don't want it, your property will not be divided/changed.
No, see above. Typically, already 20% of the area goes away for public needs (traffic areas and the like) during reallocation.
The property lies exactly in the middle of the area
That makes it clear that it cannot be excluded.
and the development costs have already been mentioned to us.
Accordingly, the whole matter is already underway: resolution to prepare, search for development contractors.
Yes, such a small green area does every area good.
As a retention area or to fulfill part of the compensation measures integrated right away, hehe.