It is extremely unlikely any kind of pmt to pub conversion exists, in context of exporting old Adobe PageMaker template files (.pmt). If you want to export Adobe PageMaker content, you have to export .pdm files, and even that will be extremely difficult today, if you do not have access to the original software.
As far as we know, no 3rd party software supports old PageMaker files of any kind. So the only way how to to work with PageMaker files is to find old copy of it. Perhaps abandonware like the WinWorld library can be of help.
Updated: January 5, 2024