I would like to fit a drawing e.g. on a A4 page but still would like to work with the real numbers and units.
Inkscape allows to work e.g. in mm, cm and m. However, not in µm (Mikrometer) or km.
Desirable would also be some arbitrary scales like 10:1, 2:1, 1:5, etc.
But I haven't found a feature to change the drawing scale. Is there such a feature? If yes, where? If not, why not?

There was an earlier post asking about how to drawing in µm, however, without practical suggestions. Scaling the objects in the drawing back and forth or post processing of the .svg file is not a practical way for me.
Are there any new features or solutions since then?
Thanks for suggestions!