Hello Urmel,
every type of construction has its advantages and disadvantages.
The big advantage of a prefabricated house is the relatively short construction time (on site), since all wall, ceiling, and roof elements are already prefabricated in the factory. However, these are usually catalog houses; special wishes also cost accordingly more. After completion in the factory, change requests are hardly possible anymore. In the timber frame construction method, which most prefabricated house manufacturers use, careful execution must be strictly observed, because otherwise considerable and even dangerous construction defects can occur.
A solid stone-on-stone house requires a significantly longer construction phase on site. Individual floor plan wishes can be realized much more easily already during the planning phase. In cooperation with a good architect or structural engineer, such a house can also be planned to be future-proof. Children come along, they grow up, eventually move out or bring partners home. Many things change over the course of a life; life is not rigid. A well-planned house from the beginning allows most changes to be made without too much effort.
In my experience, a locally solidly built residential house is usually also cheaper to build than a prefabricated house of the same size. Architect and engineer fees are included in the purchase price of a prefabricated house.
If you build a house in cooperation with the architect or structural engineer you trust, you always have your own freedom of decision and full cost transparency (which craftsman should carry out which trade at what price, which trade do I want to do myself and how much money do I save as a result, etc.).
However, anyone who wants to contribute a lot of their own work must also know that this requires a lot of time on the construction site. More than about 20% of the construction costs can only very rarely be saved through classic self-performed work. Usually the savings do not exceed 10 to 15%, and this already means a lot of hands-on work.
In my opinion, the value retention of a solidly built residential house is considerably higher than that of a prefabricated house in timber frame construction.
From these descriptions, it is already clear that I am more of an advocate of the classic "stone on stone" method.
I also consider it the right approach to first look for the plot. However, it cannot hurt to consult your architect/structural engineer even at this stage. They can tell you exactly what is possible and what is not on the intended plot.
I hope that makes the decision a little easier now.