Okta workflows: Add new user to specific group on the morning of their start date

I am looking for a way to leverage Okta workflows to add new employees to a specific Okta group based on their start date. For instance, if a user is starting monday, add them to the default group for app access at 8am. This way they arent accessing applications before their actual start date. I already have the "Start date" attribute in both Google and Okta.

I feel as though i have seen this in action at a previous job, but im not sure how to accomplish it. Any help is appreciated!