When will istio support lazy loading problems configured by envoys?

My company and I are users of Istio,now the memory of the istio-proxy is too big, and we can find it because the envoy caches a lot of the configuration of the application. Envoys start a lot of listening because of the large clusters and the number of PODs in namespaces. And in our micro-service model, it is almost impossible to understand the invocation relationships between services. So we can’t issue the configuration on demand. The Envoy only caches the full configuration.

After investigating the envoy delta interface can lazy load configuration. Someone has already mentioned this issue. Support delta_grpc ADS API · Issue #19681 · istio/istio · GitHub
I would like to know the progress and attitude of the Istio community at present. I want to be a part of it if I can.

Are you sure you are doing all you can to scope the configuration to whats needed? For example you can use the Sidecar resource to scope configurations per namespace. For gateways you can use PILOT_FILTER_GATEWAY_CLUSTER_CONFIG and PILOT_SCOPE_GATEWAY_TO_NAMESPACE to also limit the amount of configurations.

we have more then 400 services in a namespace. Also, applications have access across namespaces.
However, most applications rely on no more than 15 services, so a lot of configuration is not effective.