Set up an AWS Direct Connect connection between the on-premises environment and the VPC where the instances are deployed. Configure routing, security groups, and ACLs. Connect to the instances by using the Direct Connect connection.

Deploy and configure AWS Systems Manager Agent (SSM Agent) on each instance. Deploy VPC endpoints for Systems Manager Session Manager. Connect to the instances by using Session Manager.

Establish an AWS Site-to-Site VPN connection between the on-premises environment and the VPC where the instances are deployed. Configure routing, security groups, and ACLs. Connect to the instances by using the Site-to-Site VPN connection.

Deploy an appliance to the VPC where the instances are deployed. Assign a public IP address to the appliance. Configure security groups and ACLs. Connect to the instances by using the appliance as an intermediary.