I finally managed to get this to work successfully. Initially, when I created the event, I only set the start date because it was meant to be a day-long event. Unfortunately, it seems that setting an all-day event isn't possible through the automation process. Google Calendar automatically sets the end date based on my Google Calendar preferences. So, when I tried to update the event date to a later time, I was only updating the start date. In most cases, the start date was going to be delayed, causing the start date to be after the end date. As a result, the event wasn't updated, although the automation history still showed it as successful.

In cases where the date was moved up (earlier), the start date successfully moved, but the end date remained the same, resulting in an event that spanned multiple days. To resolve this, I added the end date to my update action. Initially, the event successfully moved with the first update, but subsequent updates failed to update the event, even though the automation history indicated success.

Upon investigating further, I discovered the issue. When I created the record, I placed the record ID in the location field of the event so that I could use it to locate the correct record. However, I didn't include the location in my update action because I wasn't making any changes to that field. Consequently, the update action cleared the location field. After the first update, I had no way to find the record again since the location field was now empty. Once I added the location to my update action, everything worked as expected.

Interestingly, when I didn't include the end date in my update, it retained the value, but it didn't do the same for the location. It's not a major issue now that I understand how it works, but it was a bit confusing initially. Hopefully, this thread will help others in the future who encounter this issue. It would be beneficial if changes to dates triggered the automation, such as when the due date changes from any value to any value. Additionally, having the ability to identify an event as an all-day event would be useful. Although it's possible to set the start and end times at the beginning and end of the day, it doesn't appear the same way on the calendar as an all-day event.

Google Calendar Update Event Automation - Not updating Google Calendar