Unity 6000.3.5f2

I've encountered a very strange performance issue that I haven't been able to solve for several days.

When I move the mouse quickly, the frame rate drops sharply from 700 to 30 (the camera doesn't move). As soon as I stop moving the mouse, the frame rate returns to normal. This happens even in an empty scene with only a camera and a directional light, even in a new project (and even in the build).

I've already disabled everything possible: HDR, SSAO, MSAA, all post-effects, shadows, V-sync, etc.

I've tested the old input manager and the new input system.