SharePoint Online/PnP/PowerShell: Update the workflow subscription by setting it to enabled to false

I finally found a solution:

$ctx = Get-PnPContext
$lst = Get-PnPList -Identity "Lists/list_Name"
$wfs = Get-PnPWorkflowSubscription -Name "WF_Name" -List $lst

$WorkflowServicesManager = New-Object Microsoft.SharePoint.Client.WorkflowServices.WorkflowServicesManager($ctx, $ctx.Web)
$WorkflowSubscriptionService = $WorkflowServicesManager.GetWorkflowSubscriptionService()
$ctx.Load($WorkflowServicesManager)
$ctx.Load($WorkflowSubscriptionService)
$ctx.ExecuteQuery()

$wfs.Enabled = $false

$WorkflowSubscriptionService.PublishSubscriptionForList($wfs, $lst.Id) | Out-Null
$ctx.ExecuteQuery()

I mixed PnP and CSOM (in bold).

May be a more beautiful solution exists, but in this case it works.