I have a Microsoft notebook mouse attached to my P, but the movement is very sluggish - I don't have enough clear space on my desk to move from one side of the screen to the other. There does not seem to be any setting to modify this.
I activated a Bluetooth mouse, and this has the opposite behaviour - the pointer dashes wildly from side to side, making it almost unusable.
I have set Mouse Motion Acceleration to the Slowest value, but this doesn't seem to help.
I am using the latest Raspbian on a Pi3B+ although the mouse problem is not new.