When looking at a guest booking, go to Messages, under Automated Messages, there is a section called "Time-Based Automatic Messages (sent by triggers at a certain time)". I would like the ability to sort the trigger emails under this by time (eg. 20 days before checkin, 7 days before checkin, 1 day before checkin, day of checkin, day of checkout, 7 days after checkout) or title so that I can easily see which emails should have gone out, and what are the upcoming emails, then I can quickly see whether the status of the email matches what should have or will happen.
In the top right corner of the Triggers page, there is a Forecast button that shows Triggers' statuses based on arrival and departure and you can filter by various items. That should get you what you're looking for.