Istio custom resources performance/scalability

1

I’m wondering how much overhead can be caused by using Istio custom resources not properly.
For instance, how bad can it be if I have many (e.g., dozens or few hundreds) of VirtualServices, Gateway resources, DestinationRules, and ServiceEntries?

For instance, let’s say I have 2 destination rules like this:

apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: dr-1
  namespace: istio-system
spec:
  host: istio-egressgateway-tls.istio-system.svc.cluster.local
  subsets:
  - name: dr-1-subset
    trafficPolicy:
      loadBalancer:
        simple: ROUND_ROBIN
      tls:
        mode: ISTIO_MUTUAL
        sni: www.url1.com

---
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: dr-2
  namespace: istio-system
spec:
  host: istio-egressgateway-tls.istio-system.svc.cluster.local
  subsets:
  - name: dr-2-subset
    trafficPolicy:
      loadBalancer:
        simple: ROUND_ROBIN
      tls:
        mode: ISTIO_MUTUAL
        sni: www.url2.com

How much better/worse is this, if compared with something like the following?

apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: dr-1
  namespace: istio-system
spec:
  host: istio-egressgateway-tls.istio-system.svc.cluster.local
  subsets:
  - name: dr-1-subset
    trafficPolicy:
      loadBalancer:
        simple: ROUND_ROBIN
      tls:
        mode: ISTIO_MUTUAL
        sni: www.url1.com
  - name: dr-2-subset
    trafficPolicy:
      loadBalancer:
        simple: ROUND_ROBIN
      tls:
        mode: ISTIO_MUTUAL
        sni: www.url2.com

Thank you, I hope the question is clear enough.