Add Data validation of Alphabetically Sort Unique values using Array Formula

Hello Excel Experts,
First of all, i thank each member for their suggestion to figure out issue in below post. Currently i am too struggling with same issue and after going through below post i found the issue was with drop downs..!!
https://www.excelforum.com/excel-pro...ver-as-mu.html

Below is the code which i currently use to get sorted unique values and its definitely causing the error. How can i create drop downs (Unique and Sorted) using Array formulas and in-turn add into VBA..? Sorry i am not that used to Array formulas.. Please help.. By the way i have 5000 rows (dynamic) of data and unique values among them may be 50 or so..

Function Sorted(Rng As Range, Optional Delim As String = ",") As String
  Dim X As Long, Arr As Variant, Uniques As Variant
  Arr = Rng.Value
        With CreateObject("Scripting.Dictionary")
          For X = 1 To UBound(Arr)
            .Item(Arr(X, 1)) = 1
          Next
          Uniques = .Keys
        End With
        With CreateObject("System.Collections.ArrayList")
          For X = LBound(Uniques) To UBound(Uniques)
            .Add Uniques(X)
          Next
          .Sort
          Sorted = Join(.ToArray, Delim)
          If left(Sorted, 1) = Delim Then Sorted = Mid(Sorted, 2)
        End With
End Function

Sub allDropDowns()
 Dim unique_string1 As String

 Worksheets("SOMENAME").Select
 On Error Resume Next
    Worksheets("SOMENAME").ShowAllData
  On Error GoTo 0
     unique_string1 = Sorted(Worksheets("SOMENAME").Range("A4", Worksheets("SOMENAME").Cells(Rows.Count, "A").End(xlUp)))

 With Worksheets("Macro").Range("C9").Validation
        .Delete
        .Add xlValidateList, Formula1:="All," & unique_string1
 End With