Your new floor plan is already much better! However, the staircase is way too small: 2 m x 1.60 m is never enough. Rather 2.2 x 2.2 m. Because of that, the ground floor will not work like this. There would be space in the upper floor though. I also don’t like children's room 1. I think Gussek Haus is good, but unfortunately Regnauer doesn’t quite fit. Living room not facing the garden and entrance on the side.
Regarding sofa position: everyone is different. I, for example, like to sit on the sofa with my morning coffee and look into the garden. Or in the evening with a glass of wine or chatting with friends. Thanks to lighting, the garden still looks great in the dark. For me, the sofa facing a wall with its back to the window or the room is a no-go. Then it’s really only suitable for watching TV and it’s no wonder you don’t use it otherwise. You could also make a narrow room divider between dining and living room and hang the TV there? Someone recently had planned it that way too, maybe ?