Floor plan planning single-family house 180m2 south access - chaotic floor plans

I always find it terrible to lock Grandma in the basement. I suspect you simply want to have the dear relative close to you - but you lack ideas. Therefore, here is an alternative suggestion.

It is initially only about the layout concerning site plan, parking spaces, terraces, and paths. I would think in this direction:

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If there is not enough space, a partial rebuilding of Grandma's granny flat would also be possible.

Dear Katja, WOW. Thank you very, very much for your effort and work. We really appreciate it. Today we spoke again with the architect and have widened the floor-to-ceiling window in the basement from 1.60 to 2.30. The narrow left area, which still belonged to the storage room in the plan, will become a storage room for the [Einliegerwohnung]. You could also put the washing machine there and thus make the bathroom "freer."

What do you think about the entrance area on the ground floor?? I’m worried that it might be too tight. What do you think?

What do you think about the entrance area on the ground floor?? I'm worried that it might be too narrow. What do you think?

Sorry, I find your plan especially in the outdoor area simply dreadful. There is not a single spot on the property where one would like to stay. Where are the trash bins supposed to be? Right next to the terrace? I also find your concerns about the entrance area completely misplaced when fundamental questions that could possibly prevent approval have not yet been resolved. I also have to admit that I find the Schimu basement antisocial and cannot support it.

have widened the floor-to-ceiling window in the basement from 1.60 to 2.30.

But there is still more basement than apartment after all.

Sorry, I just find your plan creepy, especially in the outdoor area

I suppose that the wishes do not exactly align with your idea.

Living-dining area as much as possible facing south

That’s how I understand it: a south-facing garden is absolutely desired. I also had the feeling that I had read it explicitly somewhere.
Due to the orientation of the plot, complicated long paths arise, which make a nice garden area almost impossible, provided you want the garden/terrace exactly where actually the entrance should be or where the cars are parked.
I am attaching another floor plan discussion on the topic of garden orientation.
https://www.hausbau-forum.de/threads/neubau-doppelhaus-155qm-ausrichtung-grundriss-dementsprechend.48000/

I guess the wishes do not exactly align with your idea.

Yes, apparently the tiny size of the plot in relation to the building has not yet been internalized.

...We wanted a larger, contiguous garden. This only resulted on the south side because we did not want a north garden or a narrow strip to the west.

If you do not use the unbuildable setback area at the street for parking spaces and paths, you inevitably lose contiguous area, because everything is paved with paths and driveways on the north side. Plus the outside stairs to the basement and the already much too small bicycle shed. In the end, there remains a tiny area for the south terrace between cars and street, where you get roasted in the summer. I bet almost no one ever sits there, because it is noisy and way too hot. Has anything been said about the maximum height yet?

Basement granny flat is not a good idea.