Maybe this could work

Sub MergeCSVs()
    Dim FilePath1 As String
    Dim FilePath2 As String
    Dim DestSheet As Worksheet
    Dim FSO As Object 
    ' FileSystemObject
    Dim TextStream1 As Object 
    ' TextStream for first file
    Dim TextStream2 As Object 
    ' TextStream for second file
    Dim DataArray1 As Variant
    Dim DataArray2 As Variant
    Dim RowCounter As Long
    Dim ColCounter As Long
    Dim OutputRow As Long
    ' Get the file paths from the user
    FilePath1 = Application.GetOpenFilename(FileFilter:="CSV Files (*.csv), *.csv", Title:="Select the first CSV file (semicolon delimited)")
    If FilePath1 = False Then Exit Sub 
    ' User cancelled  FilePath2 = Application.GetOpenFilename(FileFilter:="CSV Files (*.csv), *.csv", Title:="Select the second CSV file (comma delimited)")
    If FilePath2 = False Then Exit Sub 
    ' User cancelled
    ' Set the destination sheet (you can change this if needed)
    Set DestSheet = ThisWorkbook.Sheets.Add(After:=ThisWorkbook.Sheets(ThisWorkbook.Sheets.Count))
    DestSheet.Name = "MergedData"
    OutputRow = 1
    ' Create FileSystemObject
    Set FSO = CreateObject("Scripting.FileSystemObject")
    ' Process the first CSV file (semicolon delimited) 
    On Error Resume Next 
    ' In case the file doesn't exist
    Set TextStream1 = FSO.OpenTextFile(FilePath1, 1) 
    ' ForReading
    On Error GoTo 0
    If Not TextStream1 Is Nothing Then
        Do Until TextStream1.AtEndOfStream
            DataArray1 = Split(TextStream1.ReadLine, ";")
            For ColCounter = LBound(DataArray1) To UBound(DataArray1)
                DestSheet.Cells(OutputRow, ColCounter + 1).Value = Trim(DataArray1(ColCounter)) 
                ' Trim to remove extra spaces
             Next ColCounter
             OutputRow = OutputRow + 1
        Loop
            TextStream1.Close
        Else
            MsgBox "Could not open the first CSV file.", vbExclamation
        End If
        '  Process the second CSV file (comma delimited)  
        On Error Resume Next 
        ' In case the file doesn't exist
        Set TextStream2 = FSO.OpenTextFile(FilePath2, 1) 
        ' ForReading
        On Error GoTo 0
        If Not TextStream2 Is Nothing Then
            Do Until TextStream2.AtEndOfStream
                DataArray2 = Split(TextStream2.ReadLine, ",")
                For ColCounter = LBound(DataArray2) To UBound(DataArray2)
                    DestSheet.Cells(OutputRow, ColCounter + 1).Value = Trim(DataArray2(ColCounter)) 
                    ' Trim to remove extra spaces
                Next ColCounter
                OutputRow = OutputRow + 1
            Loop
            TextStream2.Close
        Else
            MsgBox "Could not open the second CSV file.", vbExclamation
        End If
        ' Clean up the FileSystemObject
        Set TextStream1 = Nothing
        Set TextStream2 = Nothing
        Set FSO = Nothing
        MsgBox "CSV files merged successfully into sheet '" & DestSheet.Name & "'.", vbInformation
End Sub