As already mentioned, a well-done Q2 plus non-woven wallpaper and painting can be sufficient.
Since it is a new building, we went straight to Q3 with the idea that if new and finer wallpapers are applied someday, the filling mess is already done.
In ten years, it will be easier in an inhabited house where furniture, etc. is in the way (even if under protective foil) to just wallpaper around it, rather than also filling and sanding from Q2 to Q3, because the wallpaper that will be absolutely necessary then requires it.