Does one know if there is a way to programmatically trigger a slide change during a presentation ?
I'd like to be able to share the "transition triggers" (back and forth at least) with some other attendes when I presenting during an online meeting or a video conference.
Due to covid and thus massive usage of online meeting these days, I guess :
Does it already exist?
No.
If it's not possible, why?
Those at Google have not made the decision to implement it - perhaps because the feature has yet to be requested.
You can however change this! You can let Google know that this is a feature that is important for access to their APIs, and that you would like to request they implement it.
Google's Issue Tracker is a place for developers to report issues and make feature requests for their development services, I'd urge you to make a feature request there. The best component to file this under would be the Apps Script component, with the Feature Request
template.