Hey there, a simple search can often net many useful results: 
There's no native KM action that will execute a macOS shortcut, but it can be done via AppleScript which KM can run.
Keyboard Maestro macOS shortcuts - Google Search
Shortcuts Picker for macOS Monterey+ - Macro Library - Keyboard Maestro Discourse
Plugin for Connecting to macOS Shortcuts App - Plug In Actions - Keyboard Maestro Discourse
A Keyboard Maestro Plugin for Apple Shortcuts | ThoughtAsylum