Works for me. I simply hold down the right mouse and roll the scroll wheel. Backward decreases speed, forward increases speed.
For clarity it doesn’t change the camera speed value in the interface UI. As far as I’m aware it’s simply a multiplier effect.
There is a min/max for each speed though.
e.g. At 8 the max feels like 16, while the min feels like 4. Level 4 seems to have a range of 1-8
