Floor plan of a townhouse 150 sqm with gable roof 6 rooms

25 cm tread is not so great either. The house looks generous and then the staircase is uncomfortable.

I would rather plan like this. Swap the bedroom and bathroom side. Widen the staircase a bit to make it appear spacious and place the utility room behind the bedroom. Access to the bedroom through the dressing room. Position the head of the bed against the dressing room wall. Unless you can increase your budget, then of course you can simply widen the house. But currently everything is very tight in very small rooms. These corner cabinets in the dressing room just don't work.

I would rather throw the floor plan as a whole into the round file and think more in the direction of the suggestion by kbt09. The airspace above the entrance is impractical at this size—a light shaft that only feels like a tunnel. You can't reach the window, lamps are hard to hang, it wastes space. Instead of forcing the impression of spaciousness on too small an area, I would plan more thoughtfully and cozily like kbt09.

The bottlenecks on the ground floor cannot be fixed just by a little rearranging. Instead of a double bed, one could put up a sofa bed, but that does not solve the problems in the kitchen and dining area.

Fundamentally, it is conceivable to extend the house to the north and/or east in order to solve the issues you mentioned.

We still need to think about how to deal with the 3m here.

Maybe slightly increase the house width to the east,

I would not insist on the house shape. 9 meters width was already a challenge 10 years ago with 40cm exterior walls if you wanted the straight staircase with the central hallway. You are still at the very beginning. Everything is changeable. Also the exterior dimensions. The plot offers many possibilities to ultimately get the optimum. The planner can put in as much effort as they want, but if you take the wrong turn on the way to Rome and have to go through many construction sites, it is often more sensible to turn around and take the other path.

[*] Cloakroom is missing directly next to the door. The idea here would be to set the wall of the utility room a bit into the room to create space for a small cloakroom. [*] We do not need a cloakroom upstairs (as currently drawn) and will adjust that again. [*] Closet planning in the bedroom upstairs or in the dressing room, to then place the bed with space. One could consider reducing the children’s rooms in favor of the bedroom and on the other side in favor of the bathroom upstairs.

I do not see any reason to straighten, correct, or even reduce rooms of reasonable size here. And honestly? The closet in the hallway, for me, is the best thing upstairs.

Utility garden, greenhouse: possibly

If that is planned, then I would definitely place the kitchen towards the utility garden with a direct outside/terrace door.

Straight concrete staircase to the upper floor because of dogs and for parking space underneath (built-in cabinets)

Cabinets under a staircase have the property of not having a consistent height at the top. You can do it… With this floor plan, I would go for the solution to rotate the staircase. But I would rather redesign and then also go more in width. However, I did not want to be seen as narrow-minded, so I looked at the plan again. And I noticed that the closets in the children’s rooms don’t even have a depth of 60? And then this here: How wide might the bed be here? The utility room closet is at least deeper than the one in the children’s room… Is that a home trainer?

And I noticed that the wardrobes in the children's rooms don't have the 60 cm depth at all?

Exactly these places with doors and windows I had already criticized, that placing wardrobe spaces there is somehow not easy. That is why I strongly advise furnishing a floor plan with the furniture you really want or have. For that, you could cut these out of paper to scale and then move them around in the rooms. Setups that you like can then be photographed and saved as an image file.