Hi Aldo,
Without server side interaction, it is not possible to convert Docx to SFDT.
https://ej2.syncfusion.com/react/documentation/document-editor/web-services/
Yes, you can use axios or fetch for network request instead using XMLHTTPREQUEST. We need to send client side data to server and get back to client this is the purpose for XMLHTTPREQUEST.
Please let us know if you need any further assistance.
Regards,
Suriya M.