I'm not that experienced yet with Excel but the following works well for me for using wildcards in filenames to open files. This example requires all files to be in the same directory/folder. Yes, it is pretty simplistic.
Sub using_wildcards_to_open_files_in_excel_vba()
Dim mypath As String
Dim sFilename As String
'Suppose you have three files in a folder
' Named blank.xlsx,, ex1_939_account.xlsx, and ex1_opt 5.xlsx
'Manually open the blank.xlsx file
'The following code lines will open the second two files before closing the previously opened file.
ActiveWorkbook.Activate
mypath = ActiveWorkbook.Path
'opening xlsx file with name containing "939" and closing current file
mypath = mypath & "\*939*.xlsx"
'MsgBox mypath 'Checking
sFilename = Dir(mypath)
'MsgBox sFilename 'Checking
ActiveWorkbook.Close savechanges:=False
Workbooks.Open Filename:=sFilename
ActiveWorkbook.Activate
mypath = ActiveWorkbook.Path
'opening xlsx file with name ending in "opt 5" and closing current file
mypath = mypath & "\*opt 5.xlsx"
'MsgBox mypath 'Checking
sFilename = Dir(mypath)
'MsgBox sFilename 'Checking
ActiveWorkbook.Close savechanges:=False
Workbooks.Open Filename:=sFilename
End Sub