OK, some basic definitions, ingress is a general name for inbound rule communication egress is a general name for outbound rule communication. Now with regard to istio, the thing that enforce ingress is a virtualservice + gateway. Now when someone talks about ingress with regard to kubernetes that usually means that he is talking about ingress controller. there are few notable ingress controllers the most common one is nginx ingress controller, you can also find an ingress controller on every popular cloud provider.

With that said, you can also get the same goal using istio (i even prefer istio over ingress controller on some situations), but you need to really understand the difference between the two, and the effort that is needed to "make" each work, if all you need is some routes with some TLS, then using istio would be a overkill, but if you need to enforce a complex network policy with somewhat complex network scheme then you should use istio, i really don't see the point of using istio just for ingress routes

First let's see if there is an ingress controller installed.

kubectl get svc -A | grep ingress

then there is no nginx-ingress controller installed

this cluster is on the cloud?

AWS

EKS

there is a chance someone played with this setup, the services are suppose to be of type LB but for some reason they are not