[SalvadorP]

I can't speak to boat living because that's not a thing in portugal/spain.

But what about prefab construction? I have researched that subject quite a bit. There are several types of construction and all have their advantages and disadvantages and, in general, much like a car or a boat, they don't really increase in value. They only lose value. But, if you are not looking at a house as an investment, this is currently a much better option than regular construction.
We ended up finding and buying an abandoned house from the 70s and I am restoring it myself (no previous knowledge or experience in anything related to construction). But we seriously considered prefabs/modular homes.
They are especially good if you already own a plot of land or can buy one for cheap.