Hmm... can the property simply be expanded to the right like that? There is a path and a public green space planned there. What will happen to the path? Will the additional approx. 220 sqm be that? Will property No. 4 then have to sacrifice parts for the public path?
Unfortunately, you haven't filled in where you want to build in your profile, so it's a bit difficult to estimate prices. Maybe you could say something about the amounts you had in mind.
But, already in the first expansion stage, it’s roughly 200 to 210 sqm of living space including utility room but without garage. If I counted correctly. That’s already quite generous.
I also find the entrance extremely impractical, bicycles, as planned, need their path to the left of the garage anyway. I think there should be more developed solutions overall.
It would be good if you could upload the entire plot with measurements, including a sketch showing where access from the street is possible.
All floor-to-ceiling windows on the west side on the first upper floor .. you should also think about the furniture arrangement. It won’t look so nice if desks etc. are standing in front of the windows.
... projections cost extra ;)