I think this will do what you want - It can only cope with one lot of multiple (( & )) brackets

It only looks at cell A1 & displays the result in a message box

Code can be modified to run down a column & place the result into another column

Sub ConvertTxtToFormula()
   Dim i4Cnt As Integer
   Dim sCellTxt As String
   Dim sParam As String
   Dim sChar As String
   Dim sFormula As String
   
   Dim iPos(4) As Integer
   
   sCellTxt = Range("a1").Value
   
   For i4Cnt = 1 To Len(sCellTxt) Step 1
      sChar = Mid(sCellTxt, i4Cnt, 1)
      Select Case sChar
      Case "("
         If i4Cnt = 1 Then
            iPos(0) = 1
            iPos(1) = i4Cnt
         Else
            iPos(1) = i4Cnt + 1
         End If
      Case ")"
         If Mid(sCellTxt, i4Cnt - 1, 2) = "))" Then
            iPos(1) = i4Cnt - 1
         End If
         iPos(0) = (i4Cnt) - iPos(1)
      Case "-", "+,", "/", "*", "^"
         iPos(1) = i4Cnt
         iPos(0) = 1
      End Select
      If iPos(0) > 0 Then
         sParam = Mid(sCellTxt, iPos(1), iPos(0))
         iPos(0) = 0
         Select Case Right(sFormula, 1)
         Case "-", "+,", "/", "*", "^", ""
            sFormula = sFormula & sParam
         Case Else
            Select Case sParam
            Case "-", "+,", "/", "*", "^"
               sFormula = sFormula & sParam
            Case Else
               sFormula = sFormula & "*" & sParam
            End Select
            If sParam = ")" Then
               sParam = Trim(Mid(sCellTxt, i4Cnt + 1))
               Select Case sParam
               Case "-", "+,", "/", "*", "^"
                  sFormula = sFormula & sParam
               Case Else
                  sFormula = sFormula & "*" & sParam
               End Select
               Exit For
            End If
         End Select
      End If
   Next i4Cnt
   MsgBox sFormula
End Sub