Thanks for contacting support.
Yes, you are right about old legacy Aspose.Pdf.Generator approach has been obsolete and new Aspose.Pdf DOM approach was not recognizing the XML structure and creating empty PDF because it was based upon old XML Schema.
To generate PDF from XML using Aspose.Pdf DOM approach, you need to create XML based upon new approach. You can follow XML Schema which can be found in XML folder in Aspose.Pdf installation directory, to create XML with new structure.
However, I have modified your XML according to new model and created a PDF document by following code snippet without any issue. Please check attached output and input XML, for your reference.
Aspose.Pdf.Document doc = new Document();<o:p></o:p>
For more information, please refer to "Convert XML file to PDF" article in the API documentation. Moreover, please note that a new release of Aspose.Pdf for .NET has been launched recently with version 17.5 and it is always recommended to use latest version of the API. Please download Aspose.Pdf for .NET 17.5 from our website and in case of any further assistance, please feel free to contact us.