Without Public Access

I am currently store my media files in aws s3 bucket through offload media lite. However, I must put my bucket into public in order to serve the media files on frontend. If I block all public access, my frontend is not able to view the media files. How can I still serve media files from s3 bucket to frontend without public access?

I have tried create IAM roles attach to EC2 to access s3 bucket, but it still fail. The media files still not accessible at frontend when I block all public access.

Please advise is there any way to use offload media with block all public access on s3