Bathroom design new construction approx. 10m²

Then please take your first one - the wall in front of the window makes the whole house unsellable.

That's probably true.. and what about this? Is it technically possible with the toilet?

Top priority: Toilet as close to the shaft as possible. Otherwise, in case of a major disaster, you might have to break up the entire bathroom. The wall needs to have tilt resistance. So, on a solid wall. If it still works with the wall, then I would again refer to my suggestion from #20 and as proposed, design the extended section of the wall as a low shelf behind the tub. That could also serve stability.