Using TextJoin (Excel 2016) in VBA

I tried a number of different approaches but can't seem to get this to work. ( I kept a few statements in there as comments to go back to in case there was an eureka moment.)

I am copying unique records (relative to Head 1) from "First sheet" to "Final." Normally, I just want to copy the first instance for each cell. (Code works fine for that)
However, if the header is "Aligned" or "Global", I want all instances to be copied to the cell.
Here is my code and an example workbook attached. Thanks in advance.

Sub test()
Dim DataRng As Range
Dim i As Integer, j As Integer, k1 As Integer, k_final As Integer
Dim LstCol As Integer, LR As Integer
Dim Mytext As String

Set WSF = Application.WorksheetFunction
Set DataRng = Sheets("First sheet").Range("A1:K10")
LstCol = 11
LR = 4

For i = 2 To LstCol
    If Sheets("Final").Cells(1, i) = "Aligned" Or Sheets("Final").Cells(1, i) = "Global" Then
        Mytext = ""
        For j = 2 To LR
            k1 = WSF.Match(Sheets("Final").Cells(j, 1), WSF.Index(DataRng, 0, 1), 0)
            k_final = k1 + WSF.CountIf(WSF.Index(DataRng, 0, 1), Sheets("Final").Cells(j, 1)) - 1
'            Mytext = WSF.TextJoin("," & Chr(10), True, Sheets("First sheet").Range(Cells(k1, i) & ":" & Cells(k_final, i)))
'            Mytext = WSF.TextJoin("," & Chr(10), True, Sheets("First sheet").Range(Cells(k1, i), Cells(k_final, i)))
            Mytext = WSF.TextJoin("," & Chr(10), True, WSF.Index(DataRng, k1, i) & ":" & WSF.Index(DataRng, k_final, i))

            Sheets("Final").Cells(j, i) = Mytext
        Next j
    Else
        For j = 2 To LR
            Sheets("Final").Cells(j, i).Value = WSF.Index(DataRng, WSF.Match(Sheets("Final").Cells(j, 1), WSF.Index(DataRng, 0, 1), 0), i)
            
        Next j
    End If
Next i

End Sub