Copy data from a monthly folder into a sheet (without opening and closing workbooks)

I have a monthly journal I complete each month where I copy data from a daily workbook to another sheet.

I have code for the current day. It opens and closes the current day's sheet.

I would like to not open and close the file and also do a month's worth of data instead, so it takes all the data from all the sheets in that month's folder.

Sub getlatestfilename()
    Dim F As String, folder As String, currentyear As Integer, currentmonth As String, foldername As String, myfile As String
    Dim LatestFile As String, filetoopen As String
    Dim LatestDate As Date
    Dim LMD As Date
    Dim LR As Long
    Dim datawb As Workbook, thiswb As Workbook, ws As Worksheet
    
    ' uncomment below once happy it runs
    Application.ScreenUpdating = False
  
    Set thiswb = ActiveWorkbook
  
    currentyear = Year(Date)
    currentmonth = Format(Month(Date), "00")
  
    folder = "K:\Finance\Protected Funding Sheets\Barclays cash funding\Daily Funding Calculation\" & currentyear '& "\"
  
    F = Dir(folder & "\*", vbDirectory)
    Do While F <> ""
        If InStr(F, currentmonth) > 0 Then
            foldername = F
            'Debug.Print foldername
            folder = folder & "\" & foldername & "\"
            Exit Do
        End If
        F = Dir
    Loop
  
    ' check the month folder has been found
    If F = "" Then
        MsgBox "No " & currentmonth & " folder found..... ", vbExclamation
        Exit Sub
    End If
    'Debug.Print folder
    
    'Make sure that the path ends in a backslash
    If Right(folder, 1) <> "\" Then folder = folder & "\"
    
    'Get the first Excel file from the folder
    myfile = Dir(folder & "*.xlsx", vbNormal)
    
    'If no files were found, exit the sub
    If Len(myfile) = 0 Then
        MsgBox "No files were found...", vbExclamation
        Exit Sub
    End If
    
    'Loop through each Excel file in the folder
    Do While Len(myfile) > 0
    
        'Assign the date/time of the current file to a variable
        LMD = FileDateTime(folder & myfile)
        
        'If the date/time of the current file is greater than the latest
        'recorded date, assign its filename and date/time to variables
        If LMD > LatestDate Then
            LatestFile = myfile
            LatestDate = LMD
        End If
        
        'Get the next Excel file from the folder
        myfile = Dir
        
    Loop
    
    'Debug.Print LatestFile, LatestDate,
    
    filetoopen = folder & LatestFile
    
    'Debug.Print filetoopen
    Set datawb = Workbooks.Open(filetoopen, Password:="barclays")
    
    'select the correct sheet
    'change sheetname to what is used in the file
    'datawb.Sheets("sheetname").Activate
    
    With datawb.Sheets("Journal")
        date1 = .Range("B1")
        date2 = .Range("C1")
        bca = .Range("C16")
        bcabs41 = .Range("H19")
        bcabs42 = .Range("H20")
        csh = .Range("K15")
        cshbs42 = .Range("O15")
        cshbs43 = .Range("O16")
        cshbs432 = .Range("O18")
        cshbs44 = .Range("O19")
        'add the other required cells
    End With
    
    datawb.Close savechanges = False
    Set ws = thiswb.Sheets("Postings")
    ws.Activate
    
    'For understanding LR = Last Row
    'add variables data to the last row + 1
     With ws
         LR = .Cells(Rows.Count, 1).End(xlUp).Row
        'add the saved variables
        .Cells(LR + 1, 1) = date1
        .Cells(LR + 1, 2) = date2
        .Cells(LR + 1, 3) = bca
        .Cells(LR + 1, 4) = bcabs41
        .Cells(LR + 1, 5) = bcabs42
        .Cells(LR + 1, 6) = csh
        .Cells(LR + 1, 7) = cshbs42
        .Cells(LR + 1, 8) = cshbs43
        .Cells(LR + 1, 9) = cshbs432
        .Cells(LR + 1, 10) = cshbs44
    
        'add the other required cells
    End With
    
    Application.ScreenUpdating = True
End Sub    

You already have a section of code that loops through all files in the folder:

'Loop through each Excel file in the folder
Do While Len(myfile) > 0
   ...    
Loop

Instead of just assigning the LatestFile inside this loop, put all of your copy / paste activity inside this loop.

 Sub getlatestfilename()
  Dim F As String, folder As String, currentyear As Integer, currentmonth As String, foldername As String, myfile As String
  Dim LatestFile As String, filetoopen As String
  Dim LatestDate As Date
  Dim LMD As Date
  Dim LR As Long
  Dim datawb As Workbook, thiswb As Workbook, ws As Worksheet
  
  ' uncomment below once happy it runs
  Application.ScreenUpdating = False
  
  
  Set thiswb = ActiveWorkbook
  
  currentyear = Year(Date)
  currentmonth = Format(Month(Date), "00")
  
  
  
  folder = "K:\Finance\Protected Funding Sheets\Barclays cash funding\Daily Funding Calculation\" & currentyear '& "\"
  
  F = Dir(folder & "\*", vbDirectory)
  Do While F <> ""
    If InStr(F, currentmonth) > 0 Then
        foldername = F
        'Debug.Print foldername
        folder = folder & "\" & foldername & "\"
        Exit Do
    End If
    F = Dir
  Loop
  
  ' check the month folder has been found
  If F = "" Then
    MsgBox "No " & currentmonth & " folder found..... ", vbExclamation
    Exit Sub
  End If
  'Debug.Print folder
      
    
    'Make sure that the path ends in a backslash
    If Right(folder, 1) <> "\" Then folder = folder & "\"
    
    'Get the first Excel file from the folder
    myfile = Dir(folder & "*.xlsx", vbNormal)
    
    'If no files were found, exit the sub
    If Len(myfile) = 0 Then
        MsgBox "No files were found...", vbExclamation
        Exit Sub
    End If
    
    'Loop through each Excel file in the folder
    Do While Len(myfile) > 0
    

        filetoopen = folder & myfile
        
        'Debug.Print filetoopen
        Set datawb = Workbooks.Open(filetoopen, Password:="barclays")
        
        'select the correct sheet
        'change sheetname to what is used in the file
        'datawb.Sheets("sheetname").Activate
        
        With datawb.Sheets("Journal")
        date1 = .Range("B1")
        date2 = .Range("C1")
        bca = .Range("C16")
        bcabs41 = .Range("H19")
        bcabs42 = .Range("H20")
        csh = .Range("K15")
        cshbs42 = .Range("O15")
        cshbs43 = .Range("O16")
        cshbs432 = .Range("O18")
        cshbs44 = .Range("O19")
        'add the other required cells
        End With
        
        
        datawb.Close savechanges = False
        Set ws = thiswb.Sheets("Postings")
        ws.Activate
        
        'For understanding LR = Last Row
        'add variables data to the last row + 1
         With ws
         LR = .Cells(Rows.Count, 1).End(xlUp).Row
        'add the saved variables
        .Cells(LR + 1, 1) = date1
        .Cells(LR + 1, 2) = date2
        .Cells(LR + 1, 3) = bca
        .Cells(LR + 1, 4) = bcabs41
        .Cells(LR + 1, 5) = bcabs42
        .Cells(LR + 1, 6) = csh
        .Cells(LR + 1, 7) = cshbs42
        .Cells(LR + 1, 8) = cshbs43
        .Cells(LR + 1, 9) = cshbs432
        .Cells(LR + 1, 10) = cshbs44
        
        
        'add the other required cells
        End With
        
        'Get the next Excel file from the folder
        myfile = Dir
        
    Loop
    
    
    
    Application.ScreenUpdating = True
End Sub