Nikon Rumours is reporting a "bug" for OS Catalina. Lightroom Classic doesn't detect Nikon cameras if the camera is turned on AFTER the "Start Tether Capture" command has been sent. Here's the link:
Cnet has a good review of Catalina. However, they suggest that unless you urgently need the new features, hold off for a month. That will allow enough time for updates that will stabilize the platform.