VBA Improve Loop

Hi,
I'm new to VBA and currently working with the loop. However, my VBA code seems very slow...
The purpose of my VBA is to loop the Source Workbook by merging all the outcomes.
I would be appreciated with your help..!

Here is my code,

Sub Merge()

Application.ScreenUpdating = False

Dim lastRow As Integer
Dim SourceWB As Workbook: Set SourceWB = Workbooks.Open("")
Dim TargetWB As Workbook: Set TargetWB = Workbooks.Open("")
Dim lRowCount As Integer, i As Integer
Dim WS1 As Worksheet, WS2 As Worksheet, WS3 As Worksheet
    With ThisWorkbook
        Set WS1 = .Sheets("OUTPUT_1")
        Set WS2 = .Sheets("OUTPUT_2")
        Set WS3 = .Sheets("PROCESS")
    End With

TargetWB.Sheets("PROCESS").Range("A4:Q100000").Clear
SourceWB.Activate
Application.ActiveSheet.UsedRange
lRowCount = Worksheets("SOURCE").UsedRange.Rows.Count
Application.Calculation = xlAutomatic
TargetWB.Sheets("INFO").Activate

    For i = 1 To lRowCount
        Cells(2, 5) = i
            Worksheets("INFO").Range("C4").Copy
            Worksheets("PROCESS").Range("A" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("INFO").Range("C8").Copy
            Worksheets("PROCESS").Range("B" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("BETA").Range("AC1:AJ1").Copy
            Worksheets("PROCESS").Range("K" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("BETA").Range("AQ1:AR1").Copy
            Worksheets("PROCESS").Range("S" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("INFO").Range("C5").Copy
            Worksheets("PROCESS").Range("C" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("INFO").Range("C6").Copy
            Worksheets("PROCESS").Range("E" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("INFO").Range("C11").Copy
            Worksheets("PROCESS").Range("F" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("BETA").Range("CC1").Copy
            Worksheets("PROCESS").Range("H" & i + 3).PasteSpecial Paste:=xlPasteValues
            
            Worksheets("INFO").Range("C17").Copy
            Worksheets("PROCESS").Range("I" & i + 3).PasteSpecial Paste:=xlPasteValues
    Next i

With WS3
lastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
.Range("C4:C" & lastRow).Formula = _
"=VLOOKUP($D4,Mapping!$A:$B,2,FALSE)"
.Range("C4:C" & lastRow).Value = .Range("C4:C" & lastRow).Value
.Range("I4:I" & lastRow).Formula = _
"=CONCAT(B4," & Chr(34) & "|" & Chr(34) & ",C4," & Chr(34) & "|" & Chr(34) & ",E4," & Chr(34) & "|" & Chr(34) & ",F4," & Chr(34) & "|" & Chr(34) & ",G4)"
.Range("I4:I" & lastRow).Value = .Range("I4:I" & lastRow).Value
.Range("F4:F" & lastRow).Formula = _
"=YEAR($E4)"
.Range("F4:F" & lastRow).Value = .Range("F4:F" & lastRow).Value
End With

With WS3
.AutoFilterMode = False
LRow = .Range("A" & .Rows.Count).End(xlUp).Row
LCol = .Range("A2").End(xlToRight).Column
Set RngBeforeFilter = .Range(.Cells(2, 1), .Cells(LRow, LCol))
RngBeforeFilter.Rows(1).AutoFilter Field:=9, Criteria1:="AAA"
WS3.Range("J4:T" & LRow).Copy Destination:=WS2.Range("A4")
End With

With WS3
.AutoFilterMode = False
LRow = .Range("A" & .Rows.Count).End(xlUp).Row
LCol = .Range("A2").End(xlToRight).Column
Set RngBeforeFilter = .Range(.Cells(2, 1), .Cells(LRow, LCol))
RngBeforeFilter.Rows(1).AutoFilter Field:=9, Criteria1:="<>AAA"
WS3.Range("J4:T" & LRow).Copy Destination:=WS1.Range("A4")
End With

WS3.AutoFilterMode = False

Application.ScreenUpdating = True
Application.Calculation = xlManual

SourceWB.Close

End Sub