Alertmanager configuration not changing

Hi all, quite new to alertmanager but I am seeing a very strange behaviour here. I installed the latest version using the kube-prometheus-stack chart. I have configured the values.yaml file, but alertmanager configuration does not change at all…

Even I add
alertmanager:
enabled: false

It got completely ignored…

  config:
    global:
      resolve_timeout: 5m
    route:
      group_by: [ 'alertname' ]
      group_wait: 10s
      group_interval: 10s
      repeat_interval: 1h
      receiver: 'devops'
      routes:
        # suppress
        - match:
            alertname: Watchdog
          receiver: 'null'
    receivers:
      # suppress
      - name: 'null'
      # devops
      - name: 'devops'
        webhook_configs:
          - url: '<https://www.zenduty.com/api/integration/prometheus/>&lt;key&gt;/'
    inhibit_rules:
      - source_match:
          severity: 'critical'
        target_match:
          severity: 'warning'
        equal: [ 'alertname', 'dev', 'instance' ]```

Sorted. ExternalSecret was on the way