coming after the show
there two things for the scale, what it shows unit in "A", and the actual unit of the scene "B"
View attachment 190233
and yeah, no scale allowed on dummies, it breaks things.
The trick if you have one scene all in centimeter, you save & close it. Open a new one, make it all meter scale, and then import your other centimeter scene, and it should be scaled automatically clean (without any 1000% in the objects, they will all remain at 100% scale)
anyway, good you found your way through