I launch a new Amazon Linux 2 AMI t2 micro instance in N.Virginia with all default settings (next, next, next, next...) and once up and running, I ssh into it, and no connectivity to the Internet.
I do the same in Ohio, and I have Internet connectivity (ping, traceroute, yum, etc.).
I've been comparing the VPC, IGW, Network ACL, Route Table, Subnets... no differences (other than N.Virginia has 6 subnets and Ohio 3). I wouldn't expect there would be differences as I use all defaults when launching.
N.Virginia instance does have DNS resolution, but again no connectivity.
Both are using an identical security group that has HTTP(80), SSH(22) and ICMP open inbound to all IPv4 addresses, and no outbound rules.
I found the problem, and yes, it's embarrassing. I've been too close to it, so I backed away, and going through some other configuring I was working on I noticed in N. Virginia on the page showing security groups that under "Outbound rules count" for the security group I've been using there were "0 permission entries".
True. Computers only do what you tell them to. So I added an outbound rule for all traffic all IPs and I now can ping and traceroute and yum. I don't remember removing that rule, which is why it didn't enter my imagination, but I'm the only one with access, so it must have been me. Sorry for the run-around.