MixEffect has terrific support for Siri and Shortcuts, allowing you to automate nearly everything in your ATEM switcher with shortcuts or your voice.
Read the documentation on all the Shortcut actions supported by MixEffect here.
Here is a list of sample shortcuts to get you started:
These shortcuts open MixEffect if a switcher is not currently active. The shortcut then either waits a pre-determined amount of time (MixEffect Helper) or prompts the user to tap a button (MixEffect Switcher Active) once the MixEffect has connected to a switcher.