How to get amazon SNS when a large file is uploaded to a S3 folder

You can send the S3 Event Notifications to Amazon EventBridge and use Advanced Filtering to filter the metadata's object size. Then set SNS as the target of your EventBridge when an event matches your event pattern.

Check this AWS blog post for more information about using Amazon S3 Event Notifications with Amazon EventBridge. It also contains an example on setting up a pattern that matches events for objects based on the size.

thanks that worked!