Help with Istio Operator Overlay in appending to existing list

I am trying to append to existing list. For example, updating Istiod discovery container args or include jwksResolverExtraRootCA by including additional Volumes via Istio operator Overlays.

Here is an example of overlay Patch:

        - apiVersion: extensions/v1beta1
          kind: Deployment
          name: istiod
          - path: .spec.template.spec.containers.[0].args
            - discovery
            - --monitoringAddr=:15014
            - --log_output_level=default:info
            - --domain
            - cluster.local
            - --trust-domain=cluster.local
            - --keepaliveMaxServerConnectionAge
            - 30m
            - --log_rotate_max_age
            - "7"
            - --log_rotate_max_backups
            - "10"
            - --log_rotate_max_size
            - "100" ```

I am only interested in appending to existing list rather than passing entire list as a patch.

Any suggestions welcome