Are you using it on chromium? It's the only browser I get raw mouse events from right now, so other browsers tend to be more choppy.

As for the habits, the point of this program is that it ultimately admits that far domain transfer for aim trainers is difficult regardless of what you do, so it tries to optimize in an absolute sense your motor control over your mouse. That way, regardless of scenario you'll have smoother and more efficient aim.

Yeah I tried Firefox and Chrome

EDIT: Maybe take some inspiration from Three.js? This demo works fine for Firefox and Chrome with a nice, smooth cursor that I'm used to https://threejsdemos.com/demos/camera/first-person