Concatenate Function getting Type mismatch error

I am trying to concatenate columns with the following code (I know there are many ways to do this but am trying to follow through on this idea) but it is not working, I get "Type mismatch" here:

sTemp(x) = .Transpose(.Transpose(Intersect(UNR, UNR(i, 1).EntireRow).Value2))

Thanks

Sub CCat()
Dim r1 As Range

    Set r1 = Range("A1:B1, G1:G1, I1:I1")

    ConcatA "Elements", r1
    
End Sub

Function ConcatA(shtName As String, rng As Range) As String
Dim ws as worksheet
Dim UNR As Range
Dim sTemp() As String
Dim x As Long, i As Long
    
    
    Set ws = ThisWorkbook.Sheets(shtName)
    
    If rng Is Nothing Then Exit Function
    With ws
         Set UNR = Intersect(.UsedRange, rng.EntireColumn)
    End With

 For i = 2 To UBound(UNR.Value2)
        x = x + 1
        ReDim Preserve sTemp(1 To x)
        With Application
               sTemp(x) = .Transpose(.Transpose(Intersect(UNR, UNR(i, 1).EntireRow).Value2))
        End With
 Next i

 Concat = Join(sTemp, ";")

'Post back to last column + 1
 With ws.UsedRange.Offset(, UBound(UNR.Value2) + 1).Resize(, 1)
        .Value = ConcatA
 End With

End Function