Sub Извлечь_DC()

    Dim src(), res(), arr
    Dim lr As Long, i As Long, ii As Long
    
    lr = Cells(Rows.Count, "A").End(xlUp).row
    src() = Range("A2:A" & lr).Value
    ReDim res(1 To UBound(src), 1 To 1)
    
    For i = 1 To UBound(src)
        src(i, 1) = Replace(src(i, 1), Chr(10), "")
        arr = Split(src(i, 1), ",")
        For ii = 0 To UBound(arr)
            arr(ii) = LTrim(arr(ii))
            If InStr(arr(ii), ".DC.") Then
                res(i, 1) = res(i, 1) & arr(ii) & ", "
            End If
        Next ii
        If res(i, 1) <> "" Then
            res(i, 1) = Left(res(i, 1), Len(res(i, 1)) - 2)
        End If
    Next i
    
    Range("B2").Resize(UBound(res)).Value = res()
    
    MsgBox "Готово!", vbInformation
    
End Sub

let
    Источник = Excel.CurrentWorkbook(){[Name="Таблица1"]}[Content],
    Пользовательская1 = Table.FromRecords(Table.TransformRows(Источник,each [Данные=[Данные],Результат=try Text.Combine(List.Transform(List.Select(Text.Split([Данные],","),each Text.Contains(_,"DC")),Text.Trim),", ") otherwise ""]))
in
    Пользовательская1