Planning is almost complete - Your opinion is wanted

First of all, thank you very much for the feedback.

I have considered the following changes:
It confirms some of my concerns.
As I already mentioned, I find the living room too small, and that bothers me the most. But how to change it without extending the entire shell by 2 meters?? Or making the secondary apartment even smaller?

I had also considered the approach of a prolonged "bay window" instead of a conservatory, which is 2 meters longer again, and apparently a "tolerable" solution!? That way we have 8 sqm more. Is that enough?? AND one could set up a terrace on the roof, which I consider unnecessary because 3 meters lower there is also a terrace + garden!?

Unfortunately, access to the terrace is "only" through the conservatory and the kitchen. Instead of a swinging door, a sliding door will be installed so it doesn’t collide with the chairs.

The sofa will go against the wall, no longer standing in the room. The TV is then in the room. I considered then a wall of 1.5 m height on which the TV will be mounted. Purpose of the wall: basically as a room divider and to hide the unsightly backside of the TV.

I wanted the large hallway upstairs to be like that; it is inviting and not so oppressive (there is enough of that downstairs already) and I think there is little room to shift things on the walls!?

The utility room should accommodate all the technology after all; washing machine then in the main bathroom if necessary.

We have additional storage options under the roof for seasonal clothing that is not needed at the moment, etc. We could also plan the storage room from the secondary apartment into the main apartment on the ground floor. However, then the secondary apartment would have no storage options.

oh yes and swap the kitchen with the living area in the [Einliegerwohnung]! BUT then the cooking fumes are in the middle of the room and cannot dissipate as well as by the window!?

Your idea approach is already good.
The storage room of the granny flat is, in my opinion, dispensable - I would convert it into a pure technical room.
I also think swapping the kitchen and dining area in the granny flat is a good idea. That way you can create a nice L-shaped kitchen and compensate for the lost storage room. And the fumes are not an issue either. They go just as well/poorly through the terrace door and you have them throughout the whole apartment anyway if you don’t vent outside. The window alone is not enough for that either.
Instead of a conservatory, I would extend the bay window from the kitchen area to the end of the living room. That way you get a living room with almost 34 m² and then have completely different possibilities for furnishing. Instead of a balcony, I would just put a roof on it – we do it like that as well.
I don’t like having the technical room upstairs. Electricity, water, gas meter readers, technicians, chimney sweeps have to walk through the entire private area in the house.
And as already mentioned: I would definitely swap the utility room and the kids’ bathroom upstairs – this just makes sense with your floor plan.

So I would rather start over again.
Living room too small or difficult to furnish (although I actually find the living room/kitchen combination of the granny flat almost worse), terrace only accessible through the conservatory, etc... I just find too many compromises.

And therefore the question again: Why so many corners and edges in the house structure? With a rectangular house structure, maybe more could be done and the "construction sites" that are still there now could be fixed.

And again something about the upstairs hallway: Do you now have such a large hallway? Our hallway on the upper floor is 7 sqm - it is spacious and should I tell you something else: Actually, it is almost too big! And where do you spend more time, upstairs or downstairs? What use is the "inviting" situation upstairs if there are problems with corners and edges downstairs?

I have to agree with Bauherren2014. With this house, you would be making far too many compromises. I wouldn't want to put myself through that in my own house. After all, you live in it for many years.

Who actually sees the "large, inviting" hallway upstairs? Your children's friends! And they couldn't care less! I find a large, welcoming entrance much more important. You walk in single file along the entire (long) hallway when guests come. They can only take off their jackets shortly before the living room. It's simply a long, dark corridor. I don't see any invitation into the house there.

No, I wouldn't put myself through such a crooked little house.

I like the suggestion with the bay window spanning the entire wall length. In terms of cost, it probably doesn't make much difference since a conservatory is very expensive? I can't understand the entrance area being too dark? We do have windows at the staircase, and there should be enough light coming in?