I tried that but it doesn't seem to work for me.
I can only presume I am doing something wrong; can you see what?

Option Explicit

Private Sub Worksheet_Activate()

Dim ws As Worksheet, LR As Long
Application.ScreenUpdating = False

For Each ws In Worksheets
    ws.ShowAllData
Next ws

Range("A2:L" & Rows.Count).ClearContents

For Each ws In Worksheets
    If ws.Name <> Me.Name Then
                LR = ws.Range("A" & Rows.Count).End(xlUp).Row
        If LR > 1 Then
            ws.Range("A2:L" & LR).Copy
            Range("A" & Rows.Count).End(xlUp).Offset(1, 0).PasteSpecial xlPasteValues
        
        End If
    End If
Next ws


Columns("A:K").Select
    Application.CutCopyMode = False
    ActiveWorkbook.Worksheets("Overview").Sort.SortFields.Clear
    ActiveWorkbook.Worksheets("Overview").Sort.SortFields.Add Key:=Range("A1"), _
        SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal
    With ActiveWorkbook.Worksheets("Overview").Sort
        .SetRange Range("A2:L" & Rows.Count)
        .Header = xlNo
        .MatchCase = False
        .Orientation = xlTopToBottom
        .SortMethod = xlPinYin
        .Apply
    End With

Cells.Columns.AutoFit
Columns("G:H").Select
    Selection.EntireColumn.Hidden = True

Application.ScreenUpdating = True
End Sub