I don't have much to add to the previous speakers, but I find the design of the kitchen-living room not well executed. The kitchen is somehow in the middle of the room and you sit on the sofa with your back to the room. I personally don't find that very cozy because you always have to twist your neck if something happens.
Regarding the price, I also notice that it is planned very optimistically. We started building 2 years ago, 140 sqm, and have now spent just under €500,000 for everything, including terrace, kitchen, upgrades, etc. And that without a granny flat and without a basement. For that reason, I find €700,000 really ambitious.
Personally, I would plan something smaller and instead design (or have designed) a nicer floor plan. You can get good inspiration and ideas from all the prefab house companies. Better to have something a bit smaller with a nice floor plan than simply unnecessarily big.