Lock and Unlock sheets in a shared workbook?

I have a shared workbook which is used for data entry. Once each person is done they press a button which I designed to then transfer the data from their individual worksheet. Here is where my issue is, I move the data to a "mass" sheet that keeps all the submitted data. This is how I originally planned to do this... until I found out you can't unlock or relock a sheet when a workbook is shared? I need to keep some of the sheets locked otherwise they could change stuff by accident or just do something incorrect. Any ideas for work around?

Sub SubmitData()
Dim iReply As Integer
Dim LR As Integer
Dim DestLR As Integer


Application.DisplayAlerts = False
Application.ScreenUpdating = False
ActiveSheet.Unprotect "XXXX"
ActiveWorkbook.Worksheets("SubmittedData").Unprotect "XXXX"

iReply = MsgBox(Prompt:="Do you wish to submit all data?", _
        Buttons:=vbYesNoCancel, Title:="Data Submission")
        
If iReply = vbYes Then
    ActiveWorkbook.Save ' This is done to refresh the master sheet if someone else has already submitted recently.
    ActiveSheet.AutoFilterMode = False
    Rows(2).AutoFilter
    ActiveSheet.Range("$A$2:$M$1000").AutoFilter Field:=1, Criteria1:="<>"
    
    LR = Range("A3").End(xlDown).Row
    
    If Not Sheets("SubmittedData").Range("A1").End(xlDown).Row > 100000 Then
        DestLR = Sheets("SubmittedData").Range("A1").End(xlDown).Row
    Else
        DestLR = 2
    End If
    
    Range("A3", "M" & LR).Copy
    Sheets("SubmittedData").Range("A" & DestLR).PasteSpecial Paste:=xlPasteValues
    Range("A3", "M" & LR).Delete
    Rows(2).AutoFilter
    Rows(3).Copy
    Rows("4:1000").PasteSpecial Paste:=xlPasteAll, Operation:=xlNone, SkipBlanks:= _
        False, Transpose:=False
    Rows(2).AutoFilter
    ActiveWorkbook.Save
    Application.Goto ActiveSheet.Range("A3"), True
Else 'Cancelled
    Exit Sub
End If

Application.DisplayAlerts = True
Application.ScreenUpdating = True
ActiveSheet.Protect "XXXX"
ActiveWorkbook.Worksheets("SubmittedData").Protect "XXXXX"

End Sub

Maybe I guess I keep the Master Data list on a different workbook? My problem is if I also use Conditional formatting to let them know if they already entered the data. I use this formula to verify using a named range on the "SubmittedData" worksheet....

=IF($C3<>"",COUNTIF(SubmittedData,$M3)>0)