Catalina: backup iOS devices programatically
Apple Configurator 21  has a command line utility cfgutil, which can be installed from the menubar in Apple Configurator
.

With cfgutil installed, you can run the command: cfgutil backup 

 
Apple Configurator 2 includes an Automator action too, which does the same as the above command. 

1Currently requires macOS version 10.14.6 or later.