@Matt_DeKok, welcome to the community. It seems the rule can be triggered by the switch event, but for some reason the command(action in the flow) doesn’t kick off the robot to start to clean. Have you checked the Live Log in SmartThings IDE if any error reported when this rule was executed?
Meanwhile, I don’t have the robot to test with, but you may want to try out different commands. My quick research found this post where the author had to send the following commands in the exact order to activate the vacuum:
setRobotCleanerCleaningModewith argumentautosetRobotCleanerMovementwith argumentcleaning