MacOS USB mouse button reversed - solved:

My left and right mouse buttons have ALWAYS been reversed for USB mice plugged into my 2012 Mac Mini. My USB Apple Magic Mouse works normally on this computer - left click to select. In "System Preferences --> Mouse", I could never find "Primary Mouse Button:..." within the video animated choices. But, today I discovered that if I disconnect/turn off my bluetooth Apple Magic Mouse, the vintage Mouse System Preferences appear, and "Primary Mouse Button: ◉ Left" is an available choice. USB mouse left/right button problem finally fixed! [macOS Catalina version 10.15.7. - Late 2012 Mac Mini]