Wood is flammable, and so it’s kind of out of the question. I’d build out of stone or brick, single story but larger footprint. Then of course ground source heat pump and all electric appliances, and solar nearby..
modern wood construction is more resistant to fire than steel, steel loses its structural strength when it gets hot while wood chars on the outside (becoming fire resistant) and doesn’t lose its strength
I've seen the aftermaths of a few barn fires over the past few years. These were old structures, pre-1950s based on appearance, framed with heavy timbers and clad with wood planks and a steel roof. After the fires, the timber frames were still standing on their stone foundations, charred and black, but there was nothing to be seen of the rest of the structure.
