How to change file name generation in Adobe PDFMaker Office COM addin

You are right but you may consider below workarounds:

1. When merging files in Acrobat Pro, the Action Wizard can be utilized to automate the renaming of the merged PDF based on metadata or batch processing inputs.
2. Microsoft Word VBA Macros

Sub ExportPDFWithDynamicName()
    Dim pdfName As String
    pdfName = ActiveDocument.BuiltInDocumentProperties("Title") & "_" & Format(Date, "yyyymmdd") & ".pdf"
    ActiveDocument.ExportAsFixedFormat OutputFileName:="C:\PDFs\" & pdfName, _
    ExportFormat:=wdExportFormatPDF
End Sub

3. For more advanced workflows, Acrobat’s JavaScript scripting capabilities enable automated post-export file renaming based on embedded metadata, providing a versatile solution for users handling merged PDFs.