Financing land and single-family house near Mainz

According to the development plan, one could build a small house without a basement of about 11x7.5m, 1.5 stories, gable roof on the 460sqm flat plot.

(Soil test was fine, building pre-approval already went through with these dimensions by the previous owner)

We are also considering a garage with a workshop 9x3m (along the house)

We are both employed with about €4500 net, 1 child planned. We can save about €1700 monthly.

The plot should cost €300 per sqm plus incidental costs, we estimate €160,000

We were told by solid construction companies from the region that we have to reckon with €360,000 for the house and should request €530,000 from the bank.

What do you think, is that too big a financial risk for us? Or are the numbers realistic at all?

Hello even though it is still a bit early, here are two great examples of cost-optimized, compact building with elongated floor plans:

https://www.hausbau-forum.de/threads/unser-entwurf-fuer-ein-guenstiges-haus.34041/post-494992
https://www.hausbau-forum.de/threads/welchen-fertighaus-anbieter-preise-erfahrungen.32592/post-441621

Personally, the statement with 360,000 € for the house would be too vague for me.

What is already included in the 360k? What about the garage, how much are the incidental construction costs, and do you have a buffer for the specifications, outdoor facilities, painting and flooring, kitchen, and possibly additional furniture?

Allegedly, the garage and the not yet mentioned balcony are included in the €360,000. The gentleman estimated additional construction costs at €20,000. That also seemed a bit low to me.