Setting a specific helm list value using set during resource "helm_release" creation

I am creating helm_release resources to deploy some helm charts . And passing some configurations using ‘set’ to be over written in helm values.

  - name: db-instance
    replicas: 1
      - "ReadWriteOnce"
      # storageClassName: oci-bv-retain
          storage: 5Gi

Now in above configuration I just wanted to change only one value inside instances, say, ‘replicas’ from my terraform helm_release block and use the rest as default (written in values.yaml). How can I acheive that ?

Currently I have tried with

set {
    name  = "instances[0].replicas"
    value = "3"

But once I run this it asks for all the values of ‘instances’ one by one.