Understanding the Requirement: EC2 instances need to upload data to S3 without using the public internet, and on-premises servers need to consume this data.

Analysis of Options:

Interface VPC Endpoint for EC2: Not relevant for accessing S3.

Gateway VPC Endpoint for S3 and Direct Connect: Provides private connectivity from EC2 instances to S3 and from on-premises to AWS, ensuring compliance with the requirement to avoid public internet.

Transit Gateway and Site-to-Site VPN: Adds unnecessary complexity and does not provide the same level of performance as Direct Connect.

Proxy EC2 Instances with NAT Gateways: Increases complexity and costs compared to a direct connection using VPC endpoints and Direct Connect.

Best Solution:

Gateway VPC Endpoint for S3 and Direct Connect: This solution ensures secure, private data transfer both within AWS and between on-premises and AWS, meeting the compliance requirements effectively.