Regarding consumption and discipline, I agree with you. But I still firmly believe that after paying off €20,000 and with a bedroom at €5,000 per month, we can also occasionally treat ourselves to one or the other small luxury...
That reads a bit cheeky. In combination with the missing answers to my questions, I see that you still don’t understand it. We are two people, and in our first two years every euro went into some kind of crap: that then had nothing to do with consumption anymore when washing machines, vacuum cleaners, etc. had to be replaced, garden tools and dozens of trees emptied the account. It had to be! not: it could be.
But if you think so, then go ahead. I don’t believe that your calculation from the WWW calculator will be accepted as is anyway. That has never worked for anyone. In this respect, if I were you, I would first take care of an offer that provides a realistic basis for discussion here.
And even there the question is asked, in what ratio the house stands to the land. If you don’t reveal it here, it’s hard to advise. Otherwise: you can always build cheaper. Good luck.