Mouse poling rate unstabe

[Haste]

You're thinking about this wrong. It's not an issue with the mouse. It's normal that the polling rate drops when you move your mouse slowly because there are less counts to report.

if you want more counts to be reported to saturate your maximum polling rate even on slower motions, you will need to increase your mouse CPI. (and dial windows and games sensitivity down to compensate in order to keep your preferred eDPI)

[Haste]

I don't think testing polling rate with a website is reliable. The browser you are using may handle polling rate in a wrong way or something, test with mousetester instead.

Just increase your dpi and that will fix it.

Are you both saying, that you don't have this "problem"? If so, I'd like to see proof of some kind.

I'm not saying I saturate my max polling rate on slow movements. But I don't consider it an issue in the first place (unlike OP)
I guess I could if I used some crazy dpi like 30K but that's so overkill and good luck tuning your sens down enough to compensate.

I'm using 3200 dpi and that's already enough to get low input lag on the start of mouse movement.

input lag tests are available from Battlenonsense comparing different dpi values. (reliable source) video link: https://youtu.be/6AoRfv9W110?si=diKzER2h0vWq8eps