Total costs for a single-family house in 2019

You should of course also take the costs for the architect into account. If all service phases are provided, this is roughly 10% based on the construction costs on top.

I understand that one should not skimp on visible materials. But with a limited budget, I would not cancel the construction project just because compromises need to be made somewhere. Savings can be made very well on things like flooring and sanitary installations, especially because these can be easily replaced later at any time. Extreme example: you cannot add underfloor insulation once the house is built. You can always renew the flooring with high quality later.