Floor plan of a new country house in a large garden according to §34 (with demolition)

Get an offer/hear what they say with the floor plan from the providers again?

You can save yourself that. Calculated across the board, it remains at 3000€/sqm. Except for the extravagant things, the factor still applies in combination with their construction service description. Weberhaus is therefore more expensive than Danwood, but with more quality.

Find an architect and get the floor plan done properly and then look for a provider with a finished floor plan?

Exactly. Find architects and have a plan developed without a draft, but with a room program, wishes, and budget. They will also advise you.

I didn't read anything about a slope. Or overlooked it.

How do you come to (which?) slope? - I don't remember anyone mentioning it.

How do you come to (which ?) slope? - I don’t remember anyone mentioning it.

I don’t either. Hence my inquiry. There are supposed to be TEs who do not see the problem.

Let's be honest: occasional overnight guests could take a taxi home, sleep on the sofa, or use a sofa bed in an 8sqm office.

For overnight guests from the region, that might be an option. When we have overnight guests, they usually come from a distance unsuitable for a taxi. Still, the approach is completely understandable, and as an alternative to a taxi, it’s worth treating your guests to a taxi and a guest room instead of building a separate room for them. It takes decades of “occasional” guests before you’ve spent what such a room costs nowadays.

Does anyone have a tip for a sensible approach?

You’re on a good path with describing what you want. I recommend taking a moment to pause and take a small step back:

Try to put this into less architectural bullet points, but more into “prose.” Describe a typical daily routine, frequently recurring situations, favorite activities and hobbies, what makes beautiful moments for you, how you like to relax, celebrate, how you want to live with the kids, how you imagine they will grow up and how their needs will change, where the dog runs around, who works at home when and what needs arise from that – all sorts of things like that. Illustrate this with a kind of “mood board” – a collection of images that appeal to you. These can be architectural details, moods, colors, garden, light, whatever you come across. Everyone is welcome to make their own mood board.

Example: The statement “I feel very comfortable with a lot of natural light” is a different statement than the requirement “all relevant rooms facing south.” If an architect, within the framework of the building regulations and budget, finds a way to realize the requirement “lots of natural light” without a south-facing location for one or the other room, that is a solution for the first requirement in this example, but not for the second demand. Maybe you will recognize that here the “tunnel vision” you already described begins.

So: The engagement with “What is quality of life and living for me” or “How do I want to live” with an architect is the key for them to plan well for you – or the key for a provider to propose a suitable floor plan to you.

And: A simple rule helps in the selection: An architect or provider who does not engage with this falls flat as a provider. If a person really engages with your life wishes without immediately drawing rooms or having to show something, but instead asks what is behind it, you have almost found the right service provider for you. Of course, sympathy, the impression of competence, and the price level should also be taken into account.

Me neither. Hence my inquiry. There are supposed to be TE who do not see the problem.

The aerial photo in the opening post may not be a strong indication, but it does give rise to an initial suspicion of a fairly flat plot, at least not clearly favoring a basement.

And: A simple rule helps with the selection: An architect or provider who does not engage with this falls flat as a provider. If a person truly deals with your life wishes without immediately drawing any rooms or having to show something, but instead asks what lies behind it, you have almost found your service provider. Sympathy, the impression of competence, and the price level of course must also be evaluated.

Many first-time building owners today are spoiled by MRI and ultrasound and have degenerated in spatial imagination, so that they impatiently push their architects towards imaging procedures. In this respect, while I cannot approve, I can at least understand if young architects, responding to these market needs, shift into third gear and immediately put concrete surface patterns into the shopping cart of 3D simulations. When then a conservative old fart like me raises a warning finger, saying that no homework has yet been done on the conceptual level, it can only seem like spoiling the fun, because for laypeople the craft result already looks "finished." They think that if it is now worth the approval for the consumption of the expensive printer ink, it should also please the stamper at the building authority, after all they deliberately adhered to the stupid eaves height on their behalf. If it should then cost only three grand despite the right university architect to get these beautiful plans, which the general contractor only has to make price-includable, then the architect even gets five star ratings for price merit on his internet customer review. In a market economy, each generation—currently one that perceives itself as a "consumer" even when building its own home, which is actually an investment rather than consumption—gets exactly what it is willing to pay for as "quality." In a buyer’s market, every lid finds its pot. Marketing specialists (who are still paid by the pots) make sure that the lids consider themselves to be at the powerful end of the lever. Philosophically, it is quite strange to watch this activity. As an advisor who sides with the building owners, I and some colleagues endeavor to still bring projects to the goal (and not just the appearance of it). But that is already a different quality of effort than what was required with the generation of the parents of today’s building owners. And so I (still: gladly) talk to the wall to plan first before painting. But this influence on the building owners takes time—years, during which a general contractor must also survive—so I make no reproach to the supplier side for now preferring to also serve the merely apparent wishes of the customers. But you don't build the third house for yourself first if the first shot had already been a hit. I could have once ended this here with a smiling punctuation mark.

.. and, a site plan with measurements and roughly accurately drawn buildings is required in order to

[*]we would like to preserve the outbuildings. These limit the building envelope to 10x14m.
[*]The carport next to the house is intended for a camper and will be "built at some point." However, we would like to maintain the distance to the neighbor so that this is also possible. The barn already stands 6 meters on the property boundary.

to be taken into account.