Floor plan single-family house, approx. 200 sqm - comments welcome

I am refraining from any detailed criticism here – from my point of view, the shown draft is only suitable as an illustration of more confused fragments of thought. That means you can already notice some major flaws, but it is by no means yet suitable as a basis for fine-tuning. And, of course, the aforementioned planning foundations still have to be provided, because as Yvonne already noted, §34 means "requirement to fit in" and not "carte blanche."

it doesn’t work at all at the top, unless you have a floor height of 5m

Help me out of my confusion, what do you mean by that?

Get me off the hook, what do you mean by that?

With such a ceiling height, it would be possible to cover the first steps of a staircase with the ceiling, as shown here in the design, since there would still be enough space at about the 6th step to avoid hitting your head on the ceiling.

Plus, that the airspace (and I am basically a fan of airspaces!) here is quite pointless because in the literal sense of the word, there is only air beneath it... The entire area under this airspace is dead space in your floor plan – nothing can be furnished or used there, you just walk through it.

???
I don't understand.

I don't understand.

Well, you don't look up into the airspace from the sofa, from a balcony you don't look down onto the dining table, below the airspace is simply the dance floor in front of the patio door.

did not know that there are rules for the construction and placement of an airspace.

Well, an airspace like a hat under which no one walks does look a bit strange.