Would it be possible to add control of the app to Google Assistant without creating individual IFTTT recipes for each channel?
https://developers.google.com/actions/extending-the-assistant#smart_home_actions
I don't think they will be direct actions without invoking "channels" the way smart home devices can be controlled (although that would be great if they can) but it does seem feasible that you could do them via conversational commands. Here is a quote from the developer page...
"The user’s device sends the user’s utterance to the Assistant, which routes it to your fulfillment service via HTTPS POST requests."