as mixer is disabled how to config policy and telemetry
As mixer was depricated and removed in istio 1.8. its functionality move in envoy. so you can use envoy filter for policy and Authorization Policy for Denials and White/Black Listing.(https://istio.io/latest/docs/tasks/policy-enforcement/enabling-policy/) mention in starting.
Telemetry is collected using an in-proxy extension mechanism (Telemetry V2)(WebAssembly sandbox API).
here is some useful link: https://banzaicloud.com/blog/istio-mixerless-telemetry/
may be this will help you