Floor plan design new building 2 full floors + attic development

Over 200 sqm for 2 people? That is already a lot for 4 people. And whether it will be 4, you can unfortunately never say and especially rarely plan. You also don't seem to be the wealthy ones who can simply afford it (see a lot of personal contribution). I would advise you to build a house that you can afford and use well, not what you wish for. That often differs greatly....

I have not yet understood many of the framework conditions: how fixed is the strange property division (I see no specification of E/D in the development plan or quoted from it, however, the remaining plot next to you can only be built on with D) # what are official building envelopes and what are the house positions intended by the property developer, this is not clearly recognizable or distinguishable here # where do the 7.0 or 7.6 m building setbacks come from ...?

Basically, I advise against planning a semi-detached house separately (the Goakeeper thread should actually be pinned as mandatory reading on the homepage!) and I miss at least the slightest hint of thoughts to coordinate the house profiles with each other. With two and a half stories, a plot ratio of 0.6 results in a floor area ratio of 0.24 when calculated back (not fixed, but please consider it). But this is mentioned only for the sake of completeness, the budget alone will brutally right-size the house, everyone except the original poster seems convinced of that. I will not go into detail here that not only the thin walls reinforce my impression that the self-planner still has far too little sense of scale.

I wouldn't know why one would need generous space for a pantry or storage room?

I do know,... how to plan it better (what you wrote, I did not write, I mentioned something about aisles/space)... if, for example, you want to stack a sack or boxes that shouldn't be in the way.
A simple example:
Your example has 3 meters of storage space, next to it 5 meters, although the room is smaller. If you omit the cabinet at the bottom of the plan, you would have 4 meters of running space plus storage options for boxes or sacks. Much more important is it on the upper floor - there is hardly any possibility to store a suitcase, garden chair, ladder, because there is no space.

I imagine a young, pragmatically success-oriented couple who quietly go their own way, for whom doing sports together is a central focus of life. Being able to do this freely in their own home, without external constraints, is a stronger motivation for building than the desire to establish a nest. Family planning is unclear, and if a family comes about, sports and physical activity will remain central at the same time.
The house reflects the idea that it should be equipped for all possibilities and that a “that’s just how it is nowadays” mentality plays a role in the minds of the designers. In the end, the house is too big and too expensive without really solving anything well. To solve something, it helps to let go of certain things.
For example: Are you really the sofa landscape type, or do you just believe that’s how it’s supposed to be? Or: Are you hobby cooks, or do you have a rather functional approach to meal preparation? In the evenings, are you mostly in front of the TV, or reading, talking, or active? Are you “standard”? If not, don’t desperately try to build “standard.” Then ideas will come, and the attic can be, for example, a reserve for expansion if the family grows; the house entrance doesn’t have to be centrally located; the kitchen doesn’t have to meet the standard of show homes; watching TV doesn’t primarily have to happen on the ground floor; a hallway doesn’t have to be “just” a hallway…
Maybe I’m wrong, but I have the feeling that you can be more radical and consistent. Cut off what you don’t need and build the house that fits your life and not the ideas of others.

Now that a self-proclaimed drywall installer has already clad the interior walls: would you like to tell us how the house was ultimately planned?

Sure, this is how it looks now. However, the bathroom on the upper floor will be designed differently than shown in the plans, meaning the positions of the bathtub, toilet, etc.