As far as we can tell this is an issue with 30-bit displays and lag in updating the screen. In previous versions of macOS there was an option in the Get Info screen to open Audacity in low resolution. That option is apparently gone in macOS 12.
This user found a solution: https://forum.audacityteam.org/t/3-1-3-laggy-on-monterey/63863/1
– Bill