Ok, I figured it out. My Mid 2010 Mac Pro (48GB ram, 8-cores) stops at Mojave. The hacks I came across looking to get my machine to run Catalina didn't thrill me. CC suggested I find earlier application versions, I was able to take one step back with my desktop publishing applications, and they quit crashing on me. It took me a while to take-in the wide vista of application logos that came with my newly installed CC interface before I finally zero'd in on InDesign, Illustrator, Photoshop, Bridge, and Acrobat. That's all I want or need. Meanwhile, I've been watching eBay to see what the 3rd-generation Mac Pros are going for.
Thank you for listening to a cranky old typesetter who learned the trade from the guys pounding out hot metal type using Linotype and Monotype keyboards.