EKS pods use the VPC networking layer so I think they meet the criteria. They use secondary IPs attached to instances rather than virtual IPs. I’ve been able to route to them from non-EKS instances in the same VPC.
I'm curious why you think that Calico's use of iptables will have performance impacts for large clusters, and what type of performance impacts you expect (bandwidth / latency / cpu / something else?).
From my experience, Calico performs rather well in large clusters (e.g. 2k nodes, appx 100 pods / node, several hundred network policies).