Lightroom Curve- Precise curve adjustment impossible

That is weird. It’s as if there is a background process interfering with mouse moves. (If you run background utilities that modify how the mouse works, you might try disabling them temporarily.) If you only see the problem in the Curves panel and nowhere else in macOS, then I have no explanation for that. I don’t see the problem on my M1 Pro on macOS 13 or Intel Mac on macOS 14. It doesn’t seem to be something others are reporting.

I did not see you use keyboard nudging in your video, so I show it working fine in the demo below from my M1 Pro in macOS 13.6.5. The keyboard editing feature works differently than it does in Photoshop, so I wanted to make sure you know what I was talking about, because if that actually does work for you, it could be a workaround until somebody figures out why your mouse appears to be constrained or lagging.

It is true that Curves in Lightroom Classic has fewer features and shortcuts than Photoshop, but using techniques such as the Targeted Adjustment Tool and keyboard nudging, it is possible to precisely set a Lightroom Classic curve point to any of the 255 available levels, just as you can in Photoshop.