I love to use Waze and use it very often. In many occasions I already enter my trip for next morning in Waze.
But then…
I know that there is a way to not start the route now, but plan / schedule what time I need to leave tomorrow morning.
I also know that Waze will message me when to leave.

However, this is really really not intuitive in the App. And I know what I am talking about, working as designer and architect in the IT.
The rest of the UI is very good, but this is really not logical or intuitive and I advise you to improve that.