The next step is taken, I had my first online meeting with the architect, a Portuguese friend whom I have seen many times already and know what he can do.
I have seen many interesting prefab options, but they are rather expensive, especially for their size and most of the time built as modules, which can not be delivered to the plot. and some companies will not build < 100m2 (I need way less). Building with flatpacks would be another option, but you get only an outer frame/shell and when finished it will be rather expensive again for just a few m2.
So I have decided to go for this in-between option and that is building sort of prefab/flatpack but with an architect who will incorporate the existing nature and levels of the terrain (no big changes, so little impact) in a rather modern design adapted to the Portuguese climate (cooling and heating). The building part will be very straightforward and fast. So maybe all finished in 2022.
Below are the first fast sketches.