How do you imagine that? There is nothing except your vague description of what is included or what the seller told you should be included.
How should one assess the costs for additional foundation work if one doesn’t even know what is included with the general contractor? 30cm? 40cm? A strip foundation goes down 80-100cm.
What does your plot look like? Do you need to replace soil? Do you need to raise the ground? What foundation does the geologist recommend?
Just for the strip foundation, without the deep foundation underneath, we paid 15,000 EUR. You won’t get far with your 6,000 EUR.
You are also deceiving yourself on the other items.
10,000 EUR for exterior work? No way.
15,000 EUR for a kitchen... only if you buy it at Pino or Nobilia and appliances from Privileg...
10,000 EUR for painting... sure, if the painter just glues fleece onto Q2 plaster... but then you might as well paint yourself...
9,000 EUR for floors... I paid just under 9,000 EUR for the floors. Tiles in kitchen and hallway (not included for me) 4,500 for just under 30m²... done by the tiler, because I didn’t trust myself with 60x60 tiles.
I only managed with the 9,000 EUR because I laid the entire upper floor myself with laminate and the living room with parquet... without this own work I would easily have reached 15,000 EUR for the floors.
My prediction:
In the end, you will come out at least 15% more expensive than you think now.