Assign an EC2 instance profile with a policy granting least privilege access to the S3 bucket.

Deploy IAM user credentials on EC2 instances for S3 access.

Integrate the S3 GeneratePresignedUrl API to provide time-limited, secure access to objects for authenticated users.

Utilize the S3 GetObject API to directly handle object retrieval for users.

Reconfigure the application to proxy S3 requests, managing additional security considerations.