Catalina I haven’t had much problems with, however noticed some odd stuff. Like the Apple Menu and System Preferences it reports one update available but if I go look - nothing. Then was playing with the new TV app and went to watch one of the Apple TV+ shows and all I get is a black screen with audio when watching a show.

Then even before Catalina, my AirPods mic seems to act odd, can hardly hear it and it messses with audio output too when listening to music, sounds like I’m listening to hold music on a telephone unless I disable the mic using a third party app. I think having a old Bluetooth chip might be the reason though since I have a older MacBook while it works great on my iPhone.