When interacting with the viewport or the grid panel the cursor actually switches to a software cursor and reads the high precision data directly from your input device (aka mouse). This means that the input will feel different, generally faster, then when not interacting with these widgets. This is because it circumvents the OS mouse ballistics which slow the mouse down and produce “easing” effects depending on the speed you are moving.
This gives you 100% precision and allows us to perform endless scroll/pan type behavior, but has the negative side effect of generally slightly adjusting the cursor speed.
If you can adjust the speed of your mouse using it’s drivers instead of relying on Windows mouse ballistics you should get a more consistent movement speed.
aka. open up the fancy mouse software you hopefully have installed and adjust the sensitivity there instead of in the normal Windows dialog. Sometimes you can adjust the sensitivity on the mouse hardware itself which should also do the trick.