I don't see any difficulties there either... If you can lower the expectations a bit, and don't need new furniture, etc., it will work. Only if you still need a new kitchen, then realize you have far too few pieces of furniture, and so on... then it gets tight.
The outdoor area won't work within that budget. We really have very little to do. A staircase, a few standpipes, a pointed protection around the house, and a few square meters of cheap paving... the cheapest offer was €5000. And that does not include a fence, lawn, or garden shed ordered yet.
If we had wanted to, or rather had to: we would have taken a small 110sqm house, and first paid the flat rate of €175,000 without floors and walls.
Added to that would be:
about €8000 for wallpaper and tiles.
about €2500 mandatory additional costs during the sampling
and about €10,000 for a few extras. (ventilation system, for example)
we would still be under €200,000 here.
Each house level would have cost about €10,000 more.
Maybe you expressed yourself incorrectly, Malo... you are excluding the incidental construction costs. I think for €220,000 every prefab house provider can offer you a house.
What you should consider are the costs that come after the house is set up. You need another €5000 if it is to be livable. For a new table, an insane number of lamps, if you don't already have some, mailbox, etc... stuff like that always costs at least a hundred euros and more, it adds up.