A company has many application VPCs that use AWS Site-to-Site VPN connections for connectivity to...

A company has many application VPCs that use AWS Site-to-Site VPN connections for connectivity to an on-premises location. The company's network team wants to gradually migrate to AWS Transit Gateway to provide VPC-to-VPC connectivity.

The network team sets up a transit gateway that uses equal-cost multi-path (ECMP) routing. The network team attaches two temporary VPCs to the transit gateway for testing. The test VPCs contain Amazon EC2 instances to confirm connectivity over the transit gateway between the on-premises location and the VPCs. The network team creates two new Site-to-Site VPN connections to the transit gateway.

During testing, the network team cannot reach the required bandwidth of 2.5 Gbps over the pair of new Site-to-Site VPN connections.

Which combination of steps should the network team take to improve bandwidth performance and minimize network congestion? (Select THREE.)