How to stop Screen Flickering when Code Hides and Unhides Rows

I already tried the

Application.ScreenUpdating = False

'My Code

Applications.ScreenUpdating = True

Here is my complete code so you get an idea of what is happening:

Private Sub Worksheet_PivotTableUpdate(ByVal Target As PivotTable)
  
  Application.ScreenUpdating = False



    Dim slItem As SlicerItem
    Dim slCache As SlicerCache
    Dim NumVal As Double
    Dim AcctManagerNm As String
    Dim rng As Range
    Dim x As Long
    
Worksheets("OfficeScoreCard").Range("E15:E767").EntireRow.Hidden = False
Worksheets("OfficeScoreCard").Range("E18:E767").ClearContents

Set rng = Worksheets("OfficeScoreCard").Range("E15")
Set pt = Target
Set pt = Worksheets("Data").PivotTables("pvt_Census")
Set slCache = ActiveWorkbook.SlicerCaches("Slicer_EmployeeNm1")


With slCache
        For Each slItem In .VisibleSlicerItems
            If slItem.HasData = True Then
                AcctManagerNm = slItem.Name
                NumVal = pt.GetPivotData("Count of EmployeeNm", "EmployeeNm", AcctManagerNm)
                If NumVal > 0 Then
                    x = x + 3
                    rng.Offset(x, 0).Value = AcctManagerNm
                End If
            End If
        Next
    End With
    

Worksheets("OfficeScoreCard").Range("E" & x + 18 & ":E767").EntireRow.Hidden = True


Application.ScreenUpdating = True



End Sub

Thanks in advanced!