From my experience testing mouse smoothness with CRT monitor, from desktop pointer to fast paced FPS games, these microstutters of the image occurs because the polling rate is not equal or multiple of 120 FPS 120Hz VSync On, is one asynchronous chain. Is needed one "fix" at a constant rate, the infinite float part is the cause.
125polling / 120FPS = 1.0416* (polling samples per frame)
500 / 120 = 4.16*
1000 / 120 = 8.33*
2000 / 120 = 16.6*
But if this test is done with for example 125 FPS 125Hz VSync On, microstutter disappears. If the mouse is moving at a constant speed, all pointers are at the same distance. Same in-game turns, perfectly smooth.
125 / 125 = 1
250 / 125 = 2
500 / 125 = 4
1000 / 125 = 8
2000 / 125 = 16
Now the chain is Sync, bye bye infinite floats. With more polling, less input lag. With more FPS more toguether pointers for the same mouse speed, completely free of microstutters, at least the microstutter caused by this polling ASync. There are others sources of microstutter like FPS drops, CPU overload.
USB mouse can only work at 125Hz or doubled number from it 250, 500, 1000, etc..., can't set polling at 120, 240, 480, 960. This result in no way get 120FPS/Hz VSync On with pointer perfectly sync
With mouse at 1000Hz, the rule is 1000 / n = entire o finite float multiple of 1000
There are a long list, from 62.5 FPS/Hz up to 1000 FPS/Hz, some examples:
1000 / 1000 = 1
1000 / 960 = 1.0416*

1000 / 800 = 1.25
1000 / 360 = 2.77*

1000 / 250 = 4
1000 / 240 = 4.16*

1000 / 200 = 5
1000 / 165 = 6.06*

1000 / 144 = 6.94*

1000 / 100 = 10
1000 / 75 = 13.3*

1000 / 62.5 = 16
1000 / 60 = 16.6*
Sadly, the current most common LCD frequencies are not Sync, is nedded a custom resolution. Polling increment reduce microstutter distance, but there is always, no matter if up to 2K 4K 8K. CRT or strobed LCD highlights inaccuracies much more, if player is very sensitive to microstutters, the only way i know to remove it is Sync the chain Mouse + GPU + Monitor
Games locked at 60FPS is one double error, motion smoothness limited, by FPS and ASync polling. Developers should take note of this issue. TV also work native at 60 or 120Hz, same issue, is a plague.