As my Adobe apps -- photoshop, etc. -- were all updated to 2020 versions, things work again. I can't even remember all the things I had to do to upgrade and re-jigger other apps, but it's all working smoothly again. But *how frustrating* and irresponsible that Mac would release Catalina w/o a warning that the current Adobe apps weren't compatible! Cautionary tale: I will never be in a hurry to upgrade again.
THIS IS THE WORST OS OF ALL TIME. THIS COMPANY FELL APART WHEN STEVE DIED. NOTHING WORKS. NOTHING INSTALLS. SPENT THOUSANDS OF DOLLARS ON SOFTWARE I CAN'T EVEN INSTALL BECAUSE DUMB ASS TRUST CERTIFICATE BLAH BLAH BLAH. GOING BACK TO WINDOWS.