I'll put it this way... you can manage 1000 € in an emergency with 2500 €. But your problem is the lack of equity. Everything you have will go toward the land. There’s no buffer there. And with a 250,000 € loan, you will most likely not be able to build a house. You’ll have to deduct 40,000 € in incidental construction costs. You still don’t have the outdoor facilities, a garden, a garage, or a kitchen.
I see it a bit differently.
If the 45,000 € includes the land plus part of the incidental costs, then you don’t need to calculate 40,000 € more for incidental construction costs (of course depending on the land). @DerDa: If I remember correctly, you don’t have a garage either, right? So, in an emergency, you can do without for now. For storage, a garden shed or something similar is enough. Our future neighbors, for example, have a construction container on the property for the time being. Not pretty, but practical.
As for the kitchen, you can take it with you in an emergency, as long as it doesn’t belong to the landlord. If you don’t need additional cabinets, you put the kitchen together, put a new countertop on it, a new baseboard underneath, and that’s it. If you need new cabinets, it can possibly be more difficult if the model is no longer available.
I am of the opinion that in a structurally weak region, you can certainly manage with the prices if you don’t have unrealistic expectations. Better small and mine than big and someday on the auction block.