After doing the exercise, I noticed that when I move the object on the Y axis in blender, in Unity it moves on the Z axis.
X and Z Unity sets them negative (in blender X and Y respectively).
By accident, I noticed that Unity can’t have two materials with the same name, so if you mistakenly use the same name in a new material, Unity will assign to it the color of the first material that recognized with this name, eliminating the second color.