Maybe just a simple loop:
I haven't figured out how to replace the ".xlsx" using a wildcard, I would assume it would be either ".xlsm" or ".xlsx", you can change them in the code
Sub LoopThroughFolder()
Dim MyFile As String, Str As String, MyDir As String, Wb As Workbook
Dim sh As Worksheet
Dim s As String, n As String
Set Wb = ThisWorkbook
'change the address to suite
MyDir = "C:\Users\dmorrison\Downloads\TestFolderLoop\"
MyFile = Dir(MyDir & "*.xls*") 'change file extension
ChDir MyDir
Application.ScreenUpdating = 0
Application.DisplayAlerts = 0
Do While MyFile <> ""
Workbooks.Open (MyFile)
s = ActiveWorkbook.Name
n = Replace(s, ".xls", "") 'change the file extension
i = 1
For Each sh In Sheets
sh.Name = n & "(" & i & ")"
i = i + 1
Next sh
ActiveWorkbook.Close True
MyFile = Dir()
Loop
End Sub