Mini house - possible for 300K €?

Note that there are many (expensive) architect-designed houses included that are far from standard. However, you definitely get nice ideas; the three pictures Amazon showed me definitely look interesting.

The houses are 90% over budget, but the ideas are good. All the houses are small, but none of them feel small. Instead of glossy polished marble and oak, you just have to choose somewhat cheaper materials.
He has also already published two volumes of lowest budget houses.

I have now put my name on the applicant list for the upcoming residential area in the neighboring village of my desired village. And I also bought "Lowest Budget: New Houses under 185,000 Euros." The land prices in the surrounding residential areas/villages were 68/119/140€/sqm; since it is supposed to start in 2022, I am expecting about 150€/sqm. I now have about 35K in cash, 7K in the building savings contract, and will continue to save 1.5-2K every month. I am still looking for leftover plots. There was one, but the owner wants to hold onto it. I have not given up yet.

Sorry for digging up the thread - but did anything come of the project? Just asking out of interest, since I want to build something myself for <300T :)