Best architecture for time triggered events in serverless architecture

I am currently designing a serverless system where I want to store objects that will be used when the user defines. For example the user can say "this object will do x in 3 days." The object gets stored in the DB, and then 3 days later, an action will happen with that object.

I want this to be as real time as possible. Time driven events architecture this answer suggests using a priority queue, which I think is a great idea. But in a serverless architecture, how can I pull objects off that priority queue only after the time that the user set passes? The only way I can think to do this now is to poll the queue every so often, but it seems like it would be better if the priority queue could pop itself and take action if the object at the front of the queue is expired.

This seems like it could work https://aws.amazon.com/blogs/mt/build-scheduler-as-a-service-amazon-cloudwatch-events-amazon-eventbridge-aws-lambda/ but I worry that it's overkill or that it's not a perfect fit that will run into scaling issues.