I recently purchased a Tripp Lite INTERNET600U UPS for my 2016 MBP 15-inch laptop running Catalina 10.15.5.
When I connect up the USB, I get the "Your computer is running on battery power ..." dialog about once a minute. It would be nice to get this working. While the laptop has a battery and knows when to turn off when its battery is low, there are also external devices attached like hard drives so it would nice to gracefully shutdown when the UPS battery is low.
My current solution is to power all the disks via the USB-C ports on the laptop but that is less than ideal.