Q: Can switching inputs be used in an Alexa Routine?
Yes, it can used be in Alexa Routine. Please use "custom action" to enter command for switch inputs manually.
Please refer to the Alexa Routines webpage (https://www.amazon.com/alexa-routines/b?ie=UTF8&node=21442922011).
Custom actions let you type in anything you can normally say to Alexa as an action in a Routine. Custom actions need to be the last action in your Routine