I am trying to create externalsecrets but the template is not working and giving the below error

apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
  name: mongodb{{- $suffix }}secret 
  namespace: {{ $.Values.namespace }}
spec:
  refreshInterval: 1m
  secretStoreRef:
    kind: ClusterSecretStore
    name: {{ $.Values.mongodb.secrets.secretStore }}
  target:
    name: mongodb{{- $suffix }}secret 
    creationPolicy: Owner
    template:
      mergePolicy: Merge
      data:
        url: "mongodb://{{ .username }}:{{ .password }}@mongodb{{ $suffix }}:27017/meteor?authSource=admin"
  data:
  - secretKey: "username"
    remoteRef:
      key: {{ $.Values.mongodb.secrets.key }}
      version: latest
      property: username
  - secretKey: "password"
    remoteRef:
      key: {{ $.Values.mongodb.secrets.key }}
      version: latest
      property: password

This is the values.yaml

mongodb:
  image: mongo:4
  mongolist:
  - 2
  secrets:
    gcpSecret: test
    username: username
    password: password

Error:

Error: template: test/templates/_mongodb.yaml:103:27: executing "mongodb" at <.username>: can't evaluate field username in type []interface {}

Can you let me know what is the issue