For privileged command for named pipes, you either have to use credssp transport or a schedule task

scheduledansiblewindows

- hosts: winnode01
  gather_facts: no
  tasks:
  - name: create a schedule task
    win_scheduled_task:
      name: ovnsetguid
      description: Set OVN System Guid
      executable: C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
      arguments: -ExecutionPolicy Unrestricted -NonInteractive ovs-vsctl set Open_vSwitch . external_ids:system-id=1919
      frequency: once
      enabled:   true
      time:      "14:00:00"
  - name: Run the schedule task
    win_shell: Start-ScheduledTask -TaskName ovnsetguid