This is Blender 4.0.2. I created a cube and changed its (x, y, z) sizes. Now it seems that the Transform Geometry modifier scales its effect according to the dimensions. I would rather see transformations performed in absolute world values. How?
Also, if the dimensions of the cube are larger, I see a distortion during a rotate.
It doesn't depend on your object dimensions. Both the modifier and your dimensions depend on the object scale, which you can read in the scale field on the sidebar, right above dimensions. Dragging dimension fields is just an alternate way of changing its scale.
It depends on the scale because it (and just about every modifier, but there may be exceptions) operates in object space. Since your X scale is 0.567, 1 object space unit is only 0.567 world space meters long, when measured in the world x axis. Other axes are slightly different. Why do these operate in object space rather than world space? More than one reason, but one good reason is so that you can scale objects: you can size your fur coat to ant-man size and the fur will stay the same size, rather than being enormously huge relative to ant-man.
The distortion that you're seeing is "shear", because that's when you get when you have ordered rotation and non-uniform scale-- when you rotate (via GN) then scale in unrotated axes (via object scaling), which is what you are doing. If you scaled then rotated, you would see no shear. It depends on the order of the operations.
The solution to this (and to a bevy of other problems) is to apply scale. With your object selected, in object mode, in the 3D viewport, hit ctrl-a -> scale to apply your object's scale.
