A little correction - i've zoomed in maybe a few more times then 8x, i've just noticed - but it doesn't change the fact, that you're able to move any object in really small steps, the closer you zoom in towards them - you can tell by the tiny and exact movements in the 3D preview window ...

If you're really desperate, to move in smaller steps using the keyboard keys, instead of using the gizmo axes, then go to "Files -> Options ..." - there you select the "Unit & Coordinates" tab.
Now you can play with the settings in "Length units" and "Snapping grid resolutions" fields - each seperate or in combination with each other - like "Internal unit" to "0.0" and "Millimeters" - and "Position Grid Resolution" (and for rotation if needed "Rotation Grid Resolution") for instance to "0.1mm" or smaller ...
This should make the steps smaller, even using only the keyboard keys ...