Thanks. To confirm: You're pinging between the EC2s using their public DNS, right?
If AWS backbone is used automagically, I wonder why would anyone pay for Transit Gateways or VPC Peering rather than do mTLS between their cross-region instances or tunnel via Wireguard-esque transports like tailscale or defined.net, for example. Also, since when has this been the case, if you'd know?
I'm curious what the bandwidth charges are for EC2 to EC2 cross-region when using their public IPs / DNS? Same as VPC Peering?