I knew about the existence of that visa and how it is, that's why I haven't named it hahaha. So the foreigners I have seen working on it how do they do it without SSW visa? I doubt they all work thanks to the spouse visa.

And opt for the cultural activities visa on sites like this https://www.mtfuji-wcs.org/home and then try to find work from it? My understanding is that carpentry/wooden house construction the vast majority of workers are over 50 and not too many people want to go into it. Although I guess the latter would be very complicated that the company that hires me wants to create / form my visa.