Suggestions for the floor plan of a single-family house about 175 sqm, gable roof house

I find the draft quite good. In some places it is imho too generous. The bathroom is amazing and the hallway also seems oversized. The office, on the other hand, is rather narrow. That would be fine as an office, but as a concert hall for the piano? Is the son or daughter only supposed to practice there, or is it meant for playing music together? Unfortunately, the living room feels a bit uncomfortable since it becomes a passage room. The storage room would be too small for me due to the lack of a utility room on the upper floor. The second door takes up a lot of space and imho makes little sense. Overall not a disaster if you can handle it like this. If it were mine, with this house size I would have a pantry as well as a laundry room, and in return a little less dancing space in the bathroom and the hallway. A bit more function and less "tada".

I suppose the living room is less of a thoroughfare, as the path often leads directly to the kitchen.

What I really don’t like is the parents’ bedroom. The bed seems to want to hide itself in front of the many windows. And the left side of the bed has two doors within reach.

Yes, the hallway has the space in the wrong place. In front of the door, the space would be very practical. Alongside the stairs, rather not. I would push the WC under the stairs, reconsider the shower downstairs (maybe needed for the dog, otherwise nobody wants to shower downstairs next to the front door if there is also a shower upstairs, I think). Then the entrance niche in the hallway can be enlarged to the right. In the garage, I would probably leave out the separation between the garage and the storage room. And definitely add a door to the front, for sliding out bicycles or something like that. I can’t exactly tell if a door is drawn there.

Where is the terrace planned? Also on the southwest side? Then the kitchen would be "very far away".

The terrace is planned around the corner to the south/west and would be accessible through the large sliding windows. We thought about the path for a long time but found no other solution because I would like the kitchen to be separated from the living area and didn’t feel the path was that far...?

Correct, then it would practically not be usable as intended. On the ground floor, I would move the door to the utility room to the top of the plan so that it is opposite the garage door. This increases the usable space in the utility room and the door is not so prominently visible in the hallway. Additional note: What is the outside door in the office for? It doesn’t end on the terrace, so would it only be for bringing in dirt?

The reading bay window will definitely be shaded with venetian blinds, that’s the plan. Is that enough? I will take a look at the utility room door. The door in the office is a floor-to-ceiling window. But you’re right, actually no terrace is planned there. We had not considered that so far. Thanks for the hint! :)

What are you going to do with the large hallway? I find it a bit too big... and also too much of a pity to have an open staircase but hardly see anything of it while living there. It’s practically a hall already... almost a bit uncomfortable :( Overall, the design might work, I would also move the doors in the utility room, but one must also say that the parents' bedroom somehow seems unplanned, the hallway gets these noses left and right from the gallery due to the staircase position.... That’s because of the staircase being placed crosswise. I like that, but I’m already bothered by the furnishing of the living room here (2 opposite 2-seaters and turning your head to the TV???) and yes: the feeling of sitting in the living room between two exits. Then there’s the kitchen, which is hard to furnish (unless you like the U-shape with a dance floor in the middle)... so you could use the hallway and the kitchen as a dance floor and the living room not for watching TV, the seating window not for sitting with a view and at that point I’d already be out – out of the house – and into the recycling bin.