Is the budget for a prefab house (turnkey) realistic?

Good day everyone!

My fiancée and I have long had the dream of moving into our own house.
Now we are very interested in a turnkey prefabricated house. After a lot of research on the internet, of course, many questions have already been answered, but one thing bothers me a bit... How much do you actually pay for a turnkey prefabricated house in the end?
I have read so many experience reports where only the costs for the house are mentioned, but we all know (at least one should think so) that there are quite a few more costs involved. I’m just thinking of the land price, notary, and other incidental building costs.

I would be interested at this point to hear if you can share some experience values on how expensive a corresponding house including all costs (also land costs, etc.) was/is for you or perhaps for acquaintances/friends. Of course, this is all very individual, depending on what else you buy (e.g., garage, etc.). However, experience values are still important so that one can get an idea of what one might still be able to afford or not.

We have a maximum budget of about 300 - 350k euros for all costs. Is the whole thing including house, land, and incidental costs realistic with that price?

Thank you in advance!

Now we are very interested in a turnkey prefab house. [...]
We have a maximum budget of about 300 - 350k euros for all costs.

With the budget, I would probably rather look to see if there is possibly an interesting project by Deutsche Reihenhaus or similar nearby. [...] If you get a plot very cheaply or for free (through relatives or similar), I mightyyyy look again at those promotional houses where you basically can’t change anything, to see if there is something suitable. (But the prices there are often from the top edge of the floor slab, so the cost points already mentioned by others should be taken into account accordingly)