Building land in the middle of nowhere with the house prices?!

Exactly, according to his statement or his bank, the planned construction project is too expensive for the selected building plot/location. [...] Regarding the financial profile, I do not want to go out on a limb, as we are currently not big earners with my journeyman's wage and my wife working part-time because of the child. Equity of about €75,000 has been contributed by us.

In short and to the point: I don't see the own contribution alone explaining the different attitude of the banks. I recommend he consult another (possibly your) financing advisor, and then he should ask them for recommendations from construction companies known for the lasting quality of their projects. And as I said, you are welcome to pass on the contact details to me. If necessary, there is still room to trim costs in 160 sqm. No construction becomes impossible just because one wants to build in a rural area. Such a non-impossibility is already supported by instruments of regional development planning. Just imagine if a Volksbank declared its region as outcast. Did he simply ask a construction financier who has no "shares" in the region and who is personally an unknown customer in terms of the business relationship history?