XL 2021 Tri alphabétique dans une cellule

Option Explicit
Function LettreClas(ByVal Don As String) As String
   Dim TNb(65 To 90) As Byte, A As Byte, P As Byte
   On Error Resume Next
   For P = 1 To Len(Don)
      A = Asc(UCase$(Mid$(Don, P, 1)))
      TNb(A) = TNb(A) + 1
      Next P
   On Error GoTo 0
   For A = 65 To 90
      LettreClas = LettreClas & String$(TNb(A), A)
      Next A
   End Function

=LettreClas(A1)

Function LettreAZ(ByVal Don As String) As String
Dim t, i&, ech As Boolean, x
   If Don = "" Then Exit Function
   ReDim t(1 To Len(Don))
   For i = 1 To Len(Don): t(i) = UCase(Mid(Don, i, 1)): Next
   Do
      ech = False
      For i = 1 To UBound(t) - 1
         If t(i + 1) < t(i) Then ech = True: x = t(i): t(i) = t(i + 1): t(i + 1) = x
      Next i
   Loop Until Not ech
   LettreAZ = Join(t, "")
End Function

=JOINDRE.TEXTE(;;TRIER(STXT(A1;SEQUENCE(NBCAR(A1));1)))